Overview

Comprehensive Description

Description

Buckthorn Family (Rhamnaceae). Mountain whitethorn is a densely branched, spiny, evergreen, flat-topped native shrub, which reaches heights of 2 to 5 feet. However, at elevations, such as the Lake Tahoe Basin, it assumes a low spreading growth form. Individual plants may spread to form continuous ground cover over areas with a diameter up to 12 feet. The numerous stems terminate in a hard sharp point thus, the name whitethorn.

Whitethorn flowers form in a small, dense cluster 1 to 2 inches long. The flowers, which bloom from late spring to mid summer, have a heavy penetrating fragrance. During the flowering season, the abundant white flowers may cause areas to appear covered with snow.

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USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Alternative names

Snowbush

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USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Distribution

National Distribution

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

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More info for the term: shrub

Whitethorn ceanothus is a characteristic shrub species found in high-elevation brushfields in Baja, California, and mountains of southern California, north to southwest Oregon, and east to the western edge of Nevada [23,27,36,56]. Plants Database provides a distributional map of whitethorn ceanothus.
  • 23. Conard, Susan G.; Reed, Merton J. 2003. Ceanothus L. ceanothus, [Online]. In: Bonner, Franklin T., tech. coord. Woody plant seed manual. Washington, DC: U.S. Department of Agriculture, National Tree Seed Laboratory (Producer). Available: http://www.nsl.fs.fed.us/wpsm/index.html [2006, May 3]. [62009]
  • 27. Eberlein, Gary P. 1982. Estimating growth of young mountain whitethorn shrubs. PSW-357. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 3 p. [6351]
  • 36. Gratkowski, H. 1961. Brush problems in southwestern Oregon. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 53 p. [8596]
  • 56. Keeley, Jon E.; Keeley, Sterling C. 1988. Chaparral. In: Barbour, Michael G.; Billings, William Dwight, eds. North American terrestrial vegetation. Cambridge; New York: Cambridge University Press: 165-207. [19545]

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States or Provinces

(key to state/province abbreviations)
UNITED STATES
CA NV OR

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Regional Distribution in the Western United States

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [8]:

3 Southern Pacific Border

4 Sierra Mountains
  • 8. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. [434]

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Adaptation

Mountain whitethorn is well suited to dry open flats and rocky slopes with well-drained soils.

Public Domain

USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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California, Nevada, and Southwest Oregon. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Public Domain

USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Physical Description

Morphology

Description

More info for the terms: capsule, cover, shrub

This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available [25,47,52,74].

Whitethorn ceanothus is a native, evergreen shrub. It has a low-lying, flat-topped growth habit, especially at higher elevations, and generally reaches heights between 2 and 5 feet (0.6-1.5 m). Whitethorn ceanothus can form a continuous ground cover up to 12 feet (3.7 m) in diameter. The many short, rigid, intricately-branched stalks end in sharp spines. The numerous leaves are alternate and distinctly 3-ribbed from the base. They are small, elliptic to egg-shaped, and blunt at the tip. The leaf margins are entire or finely toothed. Flowers are in dense clusters borne on a panicle-like inflorescence. The fruit is a capsule that is slightly crested or horned and somewhat sticky at maturity. It is small, tipped by a threadlike 3-forked appendage, and 3-lobed. Each lobe has a ridge on its back and is 3-celled with each cell bearing 1 hard, round seed or nutlet. [13,25,26,47,73,74, 78,98]

Whitethorn ceanothus has high nitrogen concentrations in its foliage and soil beneath the plant due to the nitrogen-fixing bacteria Frankia spp., suggesting that it may enhance nitrogen availability for the surrounding area [75,76].

  • 13. Bolsinger, Charles L. 1989. Shrubs of California's chaparral, timberland, and woodland: area, ownership, and stand characteristics. Res. Bull. PNW-RB-160. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Experiment Station. 50 p. [7426]
  • 25. Conrad, C. Eugene. 1987. Common shrubs of chaparral and associated ecosystems of southern California. Gen. Tech. Rep. PSW-99. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 86 p. [4209]
  • 26. Countryman, Clive M. 1982. Physical characteristics of some northern California brush fuels. Gen. Tech. Rep. PSW-61. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 8 p. [4177]
  • 47. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. [21992]
  • 52. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 2 volumes]. Dissertation. [42426]
  • 73. Mozingo, Hugh N. 1987. Shrubs of the Great Basin: A natural history. Reno, NV: University of Nevada Press. 342 p. [1702]
  • 74. Munz, Philip A. 1974. A flora of southern California. Berkeley, CA: University of California Press. 1086 p. [4924]
  • 75. North, Malcolm; Oakley, Brian; Chen, Jiquan; Erickson, Heather; Gray, Andrew; Izzo, Antonio; Johnson, Dale; Ma, Siyan; Marra, Jim; Meyer, Marc; Purcell, Kathryn; Rambo, Tom; Rizzo, Dave; Roath, Brent; Schowalter, Tim. 2002. Vegetation and ecological characteristics of mixed-conifer and red fir forests at the Teakettle Experimental Forest. Gen. Tech. Rep. PSW-GTR-186. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 52 p. [47226]
  • 76. Oakley, Brian B.; North, Malcolm P.; Franklin, Jerry F. 2003. The effects of fire on soil nitrogen associated with patches of the actinorhizal shrub Ceanothus cordulatus. Plant and Soil. 254: 35-46. [60513]
  • 78. Post, R. L. 1989. Mountain whitethorn (Ceanothus cordulatus). Fact Sheet 89-64. Reno, NV: University of Nevada, College of Agriculture, Nevada Cooperative Extension. 2p. [60460]
  • 98. U.S. Department of Agriculture, Forest Service. 1937. Range plant handbook. Washington, DC. 532 p. [2387]

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Ecology

Habitat

Key Plant Community Associations

More info for the terms: hardwood, sclerophyllous, shrub

Whitethorn ceanothus has a narrow range of environments in which it thrives. It is most commonly
found within sclerophyllous shrub communities in both conifer and hardwood forests of the coast
and interior ranges of the Sierra Nevada [13,31]. In addition to the previously listed habitats,
whitethorn ceanothus also occurs in the understory of giant sequoia (Sequoiadendron giganteum)
communities/groves because of its ability to tolerate low light levels [17,45,104].

Whitethorn ceanothus is not an indicator species for any specific habitat types, but is listed as
a "moderate site indicator" in forested communities of the upper montane in the southern
and central Sierra Nevada [79].

Other overstory species commonly associated with whitethorn ceanothus are California black oak (Quercus
kelloggii), bitter cherry (Prunus emarginata), and Brewer oak (Q. garryana var. breweri).

Common understory associates of whitethorn ceanothus include: huckleberry oak (Q. vacciniifolia),
bush chinquapin (Chrysolepis sempervirens), pinemat manzanita (Arctostaphylos nevadensis),
greenleaf manzanita (A. patula), creeping snowberry (Symphoricarpos mollis), redflower currant
(Ribes sanguineum), Sierra gooseberry (R. roezlii), California hazel (Corylus cornuta var.
californica), deerbrush (Ceanothus integerrimus), prostrate ceanothus (C. prostratus),
snowbrush ceanothus (C. velutinus), Sierra mountain misery (Chamaebatia foliolosa), salal
(Gaultheria shallon), Pacific rhododendron (Rhododendron macrophyllum), and Saskatoon serviceberry
(Amelanchier alnifolia) [21,24,52,60,63,69,98].

 
  • 104. Weatherspoon, C. Phillip. 1986. Silvics of giant sequoia. In: Weatherspoon, C. Phillip; Iwamoto, Y. Robert; Piirto, Douglas D., technical coordinators. Proceedings of the workshop on management of giant sequoia; 1985 May 24-25; Reedley, CA. Gen. Tech. Rep. PSW-95. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 4-10. [9802]
  • 13. Bolsinger, Charles L. 1989. Shrubs of California's chaparral, timberland, and woodland: area, ownership, and stand characteristics. Res. Bull. PNW-RB-160. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Experiment Station. 50 p. [7426]
  • 17. Buchanan, Hayle; Biswell, Harold H.; Gibbens, Robert P. 1966. Succession of vegetation in a cut-over Sierra redwood forest. Utah Academy Proceedings. 43(Part 1): 43-48. [16543]
  • 21. Clark, Harold W. 1932. Breeding range of the Yolla Bolly fox sparrow. The Condor. 34(3): 113-117. [55592]
  • 24. Concilio, Amy; Ma, Siyan; Li, Qinglin; LeMoine, James; Chen, Jiquan; North, Malcolm; Moorhead, Daryl; Jensen, Randy. 2005. Soil respiration response to prescribed burning and thinning in mixed-conifer and hardwood forests. Canadian Journal of Forest Research. 35: 1581-1591. [60085]
  • 31. Franklin, Jerry F.; Dyrness, C. T. 1973. Natural vegetation of Oregon and Washington. Gen. Tech. Rep. PNW-8. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 417 p. [961]
  • 45. Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. 1975. The giant sequoia of the Sierra Nevada. [NPS 120]. Washington, DC: U.S. Department of the Interior, National Park Service. 180 p. [4233]
  • 52. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 2 volumes]. Dissertation. [42426]
  • 60. Kinloch, Bohun B., Jr.; Scheuner, William. 1990. Pinus lambertiana Dougl. sugar pine. In: Burns, Russell M.; Honkala, Barbara H., tech. coords. Silvics of North America. Volume 1. Conifers. Agricultural Handbook 654. Washington, DC: U.S. Department of Agriculture, Forest Service: 370-379. [13194]
  • 63. Lanini, W. T.; Radosevich, S. R. 1986. Response of three conifer species to site preparation and shrub control. Forest Science. 32(1): 61-77. [4711]
  • 69. Minnich, R. A.; Barbour, M. G.; Burk, J. H.; Sosa-Ramirez, J. 2000. California mixed-conifer forests under unmanaged FIRE REGIMES in the Sierra San Pedro Martir, Baja California, Mexico. Journal of Biogeography. 27(1): 105-129. [38479]
  • 79. Potter, Donald A. 1998. Forested communities of the upper montane in the central and southern Sierra Nevada. Gen. Tech. Rep. PSW-GTR-169. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 319 p. [44951]
  • 98. U.S. Department of Agriculture, Forest Service. 1937. Range plant handbook. Washington, DC. 532 p. [2387]

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Habitat: Rangeland Cover Types

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This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the term: cover

SRM (RANGELAND) COVER TYPES [87]:

209 Montane shrubland

419 Bittercherry

420 Snowbrush
  • 87. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. [23362]

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Habitat: Cover Types

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the term: cover

SAF COVER TYPES [29]:

207 Red fir

210 Interior Douglas-fir

211 White fir

218 Lodgepole pine

219 Limber pine

234 Douglas-fir-tanoak-Pacific madrone

237 Interior ponderosa pine

239 Pinyon-juniper

243 Sierra Nevada mixed conifer

244 Pacific ponderosa pine-Douglas-fir

245 Pacific ponderosa pine

246 California black oak

247 Jeffrey pine
249 Canyon live oak

256 California mixed subalpine
  • 29. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905]

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Habitat: Plant Associations

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: shrub

KUCHLER [62] PLANT ASSOCIATIONS:

K005 Mixed conifer forest

K007 Red fir forest

K008 Lodgepole pine-subalpine forest

K010 Ponderosa shrub forest

K018 Pine-Douglas-fir forest

K020 Spruce-fir-Douglas-fir forest

K023 Juniper-pinyon woodland

K029 California mixed evergreen forest

K034 Montane chaparral
  • 62. Kuchler, A. W. 1964. United States [Potential natural vegetation of the conterminous United States]. Special Publication No. 36. New York: American Geographical Society. 1:3,168,000; colored. [3455]

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Habitat: Ecosystem

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

ECOSYSTEMS [33]:

FRES20 Douglas-fir

FRES21 Ponderosa pine

FRES23 Fir-spruce

FRES26 Lodgepole pine

FRES34 Chaparral-mountain shrub

FRES35 Pinyon-juniper

FRES44 Alpine
  • 33. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998]

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Habitat characteristics

Whitethorn ceanothus grows best in open situations [10,17]. Dry, open flats, pine forests, rocky ridges, and washes that have well-drained soils are common sites where whitethorn ceanothus is found [23,47,52,74,98]. Areas that have been burned or logged are very favorable for populations of whitethorn ceanothus [2,27,71]. It can also survive and thrives in the shade of coniferous timber [98].

Whitethorn ceanothus is known to occur between 2,100 to 11,000 feet (650-3,350 m) in elevation [7,14,23,47,52,74, 102]

  • 10. Biswell, H. H.; Buchanan, H.; Gibbens, R. P. 1966. Ecology of the vegetation of a second-growth sequoia forest. Ecology. 47(4): 630-634. [55065]
  • 102. Vankat, John L.; Major, Jack. 1978. Vegetation changes in Sequoia National Park, California. Journal of Biogeography. 5: 377-402. [17353]
  • 14. Botti, Stephen. 1979. Natural, conditional, and prescribed fire management plan. Washington, DC: U.S. Department of the Interior, National Park Service, Yosemite National Park. 51 p. [20901]
  • 17. Buchanan, Hayle; Biswell, Harold H.; Gibbens, Robert P. 1966. Succession of vegetation in a cut-over Sierra redwood forest. Utah Academy Proceedings. 43(Part 1): 43-48. [16543]
  • 2. Allen, Barbara H.; Bartolome, James W. 1989. Cattle grazing effects on understory cover and tree growth in mixed conifer clearcuts. Northwest Science. 63(5): 214-220. [10932]
  • 23. Conard, Susan G.; Reed, Merton J. 2003. Ceanothus L. ceanothus, [Online]. In: Bonner, Franklin T., tech. coord. Woody plant seed manual. Washington, DC: U.S. Department of Agriculture, National Tree Seed Laboratory (Producer). Available: http://www.nsl.fs.fed.us/wpsm/index.html [2006, May 3]. [62009]
  • 27. Eberlein, Gary P. 1982. Estimating growth of young mountain whitethorn shrubs. PSW-357. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 3 p. [6351]
  • 47. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. [21992]
  • 52. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 2 volumes]. Dissertation. [42426]
  • 7. Barbour, Michael G. 1988. Californian upland forests and woodlands. In: Barbour, Michael G.; Billings, William Dwight, eds. North American terrestrial vegetation. Cambridge; New York: Cambridge University Press: 131-164. [13880]
  • 71. Minnich, Richard A.; Franco-Vizcaino, Ernesto. 1997. Protecting vegetation and FIRE REGIMES in the Sierra San Pedro Martir of Baja California. Fremontia. 25(3): 13-21. [40197]
  • 74. Munz, Philip A. 1974. A flora of southern California. Berkeley, CA: University of California Press. 1086 p. [4924]
  • 98. U.S. Department of Agriculture, Forest Service. 1937. Range plant handbook. Washington, DC. 532 p. [2387]

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General Ecology

Fire Management Considerations

More info for the terms: basal area, cover, fire regime, fuel, fuel loading, ladder fuels, prescribed fire, succession

Prescribed burning of whitethorn ceanothus is used in land management to increase browse [27].

The evolution of whitethorn ceanothus and fire together suggests that the use of prescribed burning is a viable management option in areas to promote whitethorn ceanothus. The use of fire to promote whitethorn ceanothus is suitable because of the fire-stimulated germination of seeds and stump-sprouting in moderate fuel consumption burns. The species adds nitrogen to the soil, possibly enhancing conifer regeneration.

Conversely, overstocked or well-established stands of whitethorn ceanothus add significantly to fuel loading. Extensive stands of whitethorn ceanothus and montane chaparral patches exhibited the greatest mean fire spread/minute and the greatest flame lengths compared to forested types [101]. Snyder [91] notes that during succession, brush cover is still significant even as the basal area of trees doubles. If these populations persist as noted they could act as ladder fuels, increasing the possibility of a stand replacing fire.

Fuel loading becomes an important factor to recognize when using prescribed fire as a land management tool. The changing fire regime in communities where whitethorn ceanothus becomes established, to infrequent, high-severity fires [16], suggests that using fire to manage whitethorn ceanothus should be done with caution.

  • 101. van Wagtendonk, Jan W.; Botti, Stephen J. 1984. Modeling behavior of prescribed fires in Yosemite National Park. Journal of Forestry. 82(8): 479-484. [50511]
  • 16. Brown, James K.; Smith, Jane Kapler, eds. 2000. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech Rep. RMRS-GRT-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 257 p. [36581]
  • 27. Eberlein, Gary P. 1982. Estimating growth of young mountain whitethorn shrubs. PSW-357. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 3 p. [6351]
  • 91. Snyder, Bill. 1996. Future fire hazard--implications of site preparation, planting and release decisions. In: Proceedings, 17th annual forest vegetation management conference; 1996 January 16-18; Redding, CA. [Redding, CA]: [Forest Vegetation Management Conference]: 133-136. [28038]

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Broad-scale Impacts of Plant Response to Fire

More info for the terms: fuel, fuel moisture, prescribed fire, tree

Dormant whitethorn ceanothus seeds in the soil can withstand temperatures up to 220 °F (105 ºC). This
ability to withstand high soil temperatures is an important survival tool and permits the seeds to
endure long heat exposure during wildland fires and then germinate and occupy burned areas. Seeds
exposed to lethal temperature regimes created by burning heavy accumulations of slash or decaying
logs are destroyed [38].

Fire removes most of the above ground whitethorn ceanothus biomass, leaving nitrogen-rich, bare mineral
soil. Following fire, patches of whitethorn ceanothus maintain higher amounts of available nitrogen for
up to 6 months on both low- and high-intensity burn plots. If these areas continue to have more available
nitrogen than other patch types, this long-term effect may enhance tree seedling growth [76].

The Research Project Summary Plant response to prescribed burning with
varying season, weather, and fuel moisture in mixed-conifer forests of
California
provides information on prescribed fire and postfire response
of many plant community species including whitethorn ceanothus.
  • 38. Gratkowski, H. 1974. Origin of mountain whitethorn brushfields on burns and cuttings in Pacific Northwest forests. Proceedings of the Western Society of Weed Science. 27: 5-8. [4898]
  • 76. Oakley, Brian B.; North, Malcolm P.; Franklin, Jerry F. 2003. The effects of fire on soil nitrogen associated with patches of the actinorhizal shrub Ceanothus cordulatus. Plant and Soil. 254: 35-46. [60513]

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Plant Response to Fire

More info for the term: shrubs

Whitethorn ceanothus responds favorably to fire. Many soil-stored seeds germinate after fire breaks seed dormancy; seedlings can account for more than half of the plants present in burn areas [34,37]. Whitethorn ceanothus also stump-sprouts after fire [25]. Burned areas stimulate nitrification through the perpetuation of nitrogen-fixing shrubs such as whitethorn ceanothus, accelerating the recycling of nutrients stored in living and dead plants [14].
  • 14. Botti, Stephen. 1979. Natural, conditional, and prescribed fire management plan. Washington, DC: U.S. Department of the Interior, National Park Service, Yosemite National Park. 51 p. [20901]
  • 25. Conrad, C. Eugene. 1987. Common shrubs of chaparral and associated ecosystems of southern California. Gen. Tech. Rep. PSW-99. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 86 p. [4209]
  • 34. Gordon, Donald T. 1970. Natural regeneration of white and red fir...influence of several factors. Research Paper PSW-58. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 32 p. [12462]
  • 37. Gratkowski, H. 1961. Brush seedlings after controlled burning of brushlands in southwestern Oregon. Journal of Forestry. 59(12): 885-888. [3392]

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Broad-scale Impacts of Fire

More info for the terms: association, duff, frequency, shrubs

A study in mixed conifer ecosystems in the Sierra Nevada, in which whitethorn ceanothus occurred, showed that if duff consumption was 64% or less, few whitethorn ceanothus shrubs were killed and few seeds were stimulated to germinate. The threshold heat load necessary to scarify high numbers of seed stored in the soil bank was very close to the threshold that can kill below ground meristematic tissues of resprouting shrubs. At consumption levels greater than 64% the number of seedlings increased exponentially while survival of resprouters decreased from 94 to 50%. If duff consumption was greater than 94% both are reduced and the heat loads are severe enough to cause a decline in the number of seeds in the soil which survive and successfully germinate [54]. A later study by Kauffman and Martin [53] done in the same mixed conifer ecosystems of the Sierra Nevada , shows that whitethorn ceanothus was more resistant to fire-induced mortality than other species found in association, such as California black oak and tanoak (Lithocarpus densiflorus). Although there were few or relatively no shrubs present on plots before burning, numbers and frequency of whitethorn ceanothus increased after burning [46,59].
  • 46. Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. 1980. Giant sequoia ecology: Fire and reproduction. Scientific Monograph Series No. 12. Washington, DC: U.S. Department of the Interior, National Park Service. 182 p. [6587]
  • 53. Kauffman, J. B.; Martin, R. E. 1990. Sprouting shrub response to different seasons and fuel consumption levels of prescribed fire in Sierra Nevada mixed conifer ecosystems. Forest Science. 36(3): 748-764. [13063]
  • 54. Kauffman, John Boone. 1986. The ecological response of the shrub component to prescribed burning in mixed conifer ecosystems. Berkeley, CA: University of California, Berkeley. 235 p. Dissertation. [19559]
  • 59. Kilgore, Bruce M. 1971. The role of fire in managing red fir forests. In: Transactions, 36th North American wildlife and natural resources conference; 1971 March 7-10; Portland, OR. Washington, DC: Wildlife Management Institute: 405-416. [6474]

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Immediate Effect of Fire

More info for the term: severity

Fire top-kills or kills whitethorn ceanothus, depending on severity [76]. It is resistant to fire-induced mortality because of the deeply buried meristematic tissues [54].
  • 54. Kauffman, John Boone. 1986. The ecological response of the shrub component to prescribed burning in mixed conifer ecosystems. Berkeley, CA: University of California, Berkeley. 235 p. Dissertation. [19559]
  • 76. Oakley, Brian B.; North, Malcolm P.; Franklin, Jerry F. 2003. The effects of fire on soil nitrogen associated with patches of the actinorhizal shrub Ceanothus cordulatus. Plant and Soil. 254: 35-46. [60513]

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Post-fire Regeneration

More info for the terms: adventitious, ground residual colonizer, shrub

POSTFIRE REGENERATION STRATEGY [93]:
Tall shrub, adventitious bud/root crown
Ground residual colonizer (on-site, initial community)
  • 93. Stickney, Peter F. 1989. FEIS postfire regeneration workshop--April 12: Seral origin of species comprising secondary plant succession in Northern Rocky Mountain forests. 10 p. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. [20090]

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Fire Ecology

More info for the terms: association, cover, fire regime, fuel, presettlement fire regime, severity

Fire adaptations: Whitethorn ceanothus is highly dependent on fire [11,14]. After fire it regenerates by stump-sprouting or from seed depending on the severity of the burn. It is characterized specifically as an obligate sprouter in moderate fuel-consumption burns and a facultative seeder following high fuel-consumption fires [25,54]. The seeds of whitethorn ceanothus are refractory: requiring heat alone or in conjunction with other conditions such as cold stratification [55]. Heat from a burn initiates germination by cracking the seed coat to allow for absorption of water [10,17,38,80,82].

FIRE REGIMES: Whitethorn ceanothus occurs in a mixed fire regime. The presettlement fire regime for communities where whitethorn ceanothus occurs consisted of frequent, low-severity burns and larger stand-replacing fires. Postsettlement, this trend has changed and produced more lethal fires with higher severities and longer intervals [16]. The fire return intervals in the montane chaparral, where whitethorn ceanothus most often occurs, are "probably quite variable" due to the influence of poor growing conditions [88]. Fire in the subalpine forest habitats where whitethorn ceanothus occurs is infrequent due to limited productivity and fuel accumulation in association with short growing season and heavy snow cover [70].

The following table provides fire return intervals for plant communities and ecosystems where whitethorn ceanothus is important. For further information, see the FEIS review of the dominant species listed below. If you are interested in plant communities or ecosystems that are not listed below, see the complete FEIS Fire Regime Table.

Community or ecosystem Dominant species Fire return interval range (years)
California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100
pinyon-juniper Pinus-Juniperus spp. <35 [77]
Sierra lodgepole pine* Pinus contorta var. murrayana 35-200
Jeffrey pine Pinus jeffreyi 5-30
Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47 [4]
interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [4,5,64]
coastal Douglas-fir* Pseudotsuga menziesii var. menziesii 40-240 [4,72,84]
California mixed evergreen Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii <35
canyon live oak Quercus chrysolepis 4]
California black oak Quercus kelloggii 5-30 [77]
*fire return interval varies widely; trends in variation are noted in the species review
  • 10. Biswell, H. H.; Buchanan, H.; Gibbens, R. P. 1966. Ecology of the vegetation of a second-growth sequoia forest. Ecology. 47(4): 630-634. [55065]
  • 11. Biswell, Harold H. 1974. Effects of fire on chaparral. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 321-364. [14542]
  • 14. Botti, Stephen. 1979. Natural, conditional, and prescribed fire management plan. Washington, DC: U.S. Department of the Interior, National Park Service, Yosemite National Park. 51 p. [20901]
  • 16. Brown, James K.; Smith, Jane Kapler, eds. 2000. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech Rep. RMRS-GRT-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 257 p. [36581]
  • 17. Buchanan, Hayle; Biswell, Harold H.; Gibbens, Robert P. 1966. Succession of vegetation in a cut-over Sierra redwood forest. Utah Academy Proceedings. 43(Part 1): 43-48. [16543]
  • 25. Conrad, C. Eugene. 1987. Common shrubs of chaparral and associated ecosystems of southern California. Gen. Tech. Rep. PSW-99. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 86 p. [4209]
  • 38. Gratkowski, H. 1974. Origin of mountain whitethorn brushfields on burns and cuttings in Pacific Northwest forests. Proceedings of the Western Society of Weed Science. 27: 5-8. [4898]
  • 4. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. [36984]
  • 5. Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. [14986]
  • 54. Kauffman, John Boone. 1986. The ecological response of the shrub component to prescribed burning in mixed conifer ecosystems. Berkeley, CA: University of California, Berkeley. 235 p. Dissertation. [19559]
  • 55. Keeley, Jon E. 1991. Seed germination and life history syndromes in the California chaparral. The Botanical Review. 57(2): 81-116. [36973]
  • 64. Laven, R. D.; Omi, P. N.; Wyant, J. G.; Pinkerton, A. S. 1980. Interpretation of fire scar data from a ponderosa pine ecosystem in the central Rocky Mountains, Colorado. In: Stokes, Marvin A.; Dieterich, John H., tech. coords. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 46-49. [7183]
  • 70. Minnich, Richard A. 1999. Vegetation, FIRE REGIMES, and forest dynamics. In: Miller, P. R.; McBride, J. R., eds. Oxidant air pollution impacts in the montane forests of southern California: a case study of the San Bernardino Mountains. Ecological Studies: Analysis and Synthesis. Vol. 134. New York: Springer-Verlag: 44-80. [30370]
  • 72. Morrison, Peter H.; Swanson, Frederick J. 1990. Fire history and pattern in a Cascade Range landscape. Gen. Tech. Rep. PNW-GTR-254. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 77 p. [13074]
  • 77. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; Gottfried, Gerald J.; Haase, Sally M.; Harrington, Michael G.; Narog, Marcia G.; Sackett, Stephen S.; Wilson, Ruth C. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-volume 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. [36978]
  • 80. Quick, Clarence R. 1935. Notes on the germination of ceanothus seeds. Madrono. 3: 135-140. [4135]
  • 82. Quick, Clarence R.; Quick, Alice S. 1961. Germination of ceanothus seeds. Madrono. 16: 23-30. [4134]
  • 84. Ripple, William J. 1994. Historic spatial patterns of old forests in western Oregon. Journal of Forestry. 92(11): 45-49. [33881]
  • 88. Skinner, Carl N.; Chang, Chi-ru. 1996. FIRE REGIMES, past and present. In: Status of the Sierra Nevada. Sierra Nevada Ecosystem Project: Final report to Congress. Volume II: Assessments and scientific basis for management options. Wildland Resources Center Report No. 37. Davis, CA: University of California, Centers for Water and Wildland Resources: 1041-1069. [28975]

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Successional Status

More info on this topic.

More info for the terms: succession, tree

Whitethorn ceanothus can be classified as both an early- and late-successional species. It is considered a pioneer species most commonly associated with early successional stages because of its ability to germinate from seed and sprout after disturbance [15,81]. Since whitethorn ceanothus is one of the 1st plants to become established on denuded soils, it has immediate value in soil protection and later serves as a nurse crop for coniferous species [98]. It is possible that whitethorn ceanothus plays an important role in succession by providing a more favorable microclimate of nutrient rich microsites in otherwise harsh growing conditions [76].

In normal seral conditions whitethorn ceanothus is overtopped and killed by the conifer species that become established in their shade. The brushfields can, however, significantly hinder conifer regeneration and slow the rate of forest succession. If there is repeated fire, whitethorn ceanothus brushfields can become semipermanent communities [31]. Where fire is lacking, it does not establish and populations decrease, and in some cases are eliminated, in the shade of dense tree canopies [10].

A study by Fernau and others [30] along the west face of the central Sierra Nevada classified whitethorn ceanothus as a late-successional species, with populations peaking 26-32 years after disturbance. Findings published by Minnich [70] also provide evidence that it is capable of existing in later successional stages. He states that chronosequences of postsuccession show the establishment of seedlings of whitethorn ceanothus without fire, apparently from seed caches.

  • 10. Biswell, H. H.; Buchanan, H.; Gibbens, R. P. 1966. Ecology of the vegetation of a second-growth sequoia forest. Ecology. 47(4): 630-634. [55065]
  • 15. Bowcutt, Frederica. 1990. Native herbaceous species used in mitigation project in Lake Tahoe basin. Restoration & Management Notes. 8(1): 38. [13778]
  • 30. Fernau, R. F.; Benayas, J. M. Rey; Barbour, M. G. 1998. Early secondary succession following clearcuts in red fir forests of the Sierra Nevada, California. Madrono. 45(2): 131-136. [30094]
  • 31. Franklin, Jerry F.; Dyrness, C. T. 1973. Natural vegetation of Oregon and Washington. Gen. Tech. Rep. PNW-8. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 417 p. [961]
  • 70. Minnich, Richard A. 1999. Vegetation, FIRE REGIMES, and forest dynamics. In: Miller, P. R.; McBride, J. R., eds. Oxidant air pollution impacts in the montane forests of southern California: a case study of the San Bernardino Mountains. Ecological Studies: Analysis and Synthesis. Vol. 134. New York: Springer-Verlag: 44-80. [30370]
  • 76. Oakley, Brian B.; North, Malcolm P.; Franklin, Jerry F. 2003. The effects of fire on soil nitrogen associated with patches of the actinorhizal shrub Ceanothus cordulatus. Plant and Soil. 254: 35-46. [60513]
  • 81. Quick, Clarence R. 1944. Effects of snowbrush on the growth of Sierra gooseberry. Journal of Forestry. 42: 827-832. [11504]
  • 98. U.S. Department of Agriculture, Forest Service. 1937. Range plant handbook. Washington, DC. 532 p. [2387]

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Regeneration Processes

More info for the terms: autogamy, breeding system, duff, frequency, layering, lignotuber, natural, shrub

Whitethorn ceanothus regenerates by seed and vegetative means. Germination from seeds stored in the soil is the primary mode of reproduction for whitethorn ceanothus and generally takes place after fire [40,54]. Prolific sprouting occurs from a lignotuber when damage is done to the top of the plant [40,50]. Whitethorn ceanothus is an obligate sprouter in moderate fuel-consumption burns and a facultative seeder following high fuel-consumption burns [53].

Pollination: Whitethorn ceanothus is an insect-pollinated species [67].

Breeding system: Outcrossing is the most common breeding system in Ceanothus spp., with limited autogamy [67].

Seed production: Ceanothus spp. are prolific seed producers. Thousands of viable seeds can be produced per hectare and remain dormant in the soil and duff layer until disturbance stimulates germination [38,48]. At approximately 4 years of age, whitethorn ceanothus is capable of seed production and reaches a maximum seed load of approximately 4,500 seeds per plant by the age of 20 to 25. Seed production remains high until the plant is senescent, around 40 years of age, or where the plants are inhibited by shade [18].

Seed dispersal: Whitethorn ceanothus seeds are autochorus, meaning that the main mode of seed dispersal is by the plant itself [55]. The seeds are small and tend to stay where they fall, unless they are carried off by birds, rodents, or ants [22,67]. Ceanothus seeds can also be forcibly ejected from the seed pods when they ripen [22,55].

Seed banking: Because of the large number of seeds produced by whitethorn ceanothus, substantial seed reservoirs exist in the soil and duff layer. The number of seeds in the soil can be expected to vary from year to year depending on the amount of seeds produced and seeds utilized by consumers [22]. Keeley [55] notes a relationship between the seed bank size and stand age where whitethorn ceanothus is found; the older the stand the larger the seed bank will be. Seed quantities of whitethorn ceanothus combined with littleleaf ceanothus (Ceanothus parvifolius) in over-mature mixed coniferous forests can number up to 1.9 million/acre [68].

Germination: Whitethorn ceanothus is heavily dependent upon fire for germination [11]. The seeds of whitethorn ceanothus are refractory: they require a heat stimulus alone or in conjunction with other conditions such as cold stratification [55]. Fire, or similar heat treatment, is necessary to crack the seed coat to allow for absorption of water and subsequent germination. Maximum germination occurs with the sequence of fire and a natural stratification period of 10 to 16 weeks [10,17,38,55,80,82]. Whitethorn ceanothus was observed to be germinating profusely on logged areas, perhaps because of heat from insolation [86].

Fire aids in the germination of seeds but can also destroy them. High intensity or high frequency fires can be detrimental to the seed bank and can result in lower rates of germination [22,68,80,82]. Overall, fire appears to be beneficial in promoting seed numbers, germination, and seedling population [52,68].

The initiation of germination depends on the following: how long the seeds had been dormant; length of time since the last soil disturbance; heat of previous fires; amount of moisture in the soil; persistence of the winter snow pack; soil temperatures; sun exposure; and how deeply the seed was buried [18].

Seedling establishment/growth: Gratkowski [37] notes that whitethorn ceanothus seedling establishment is much higher in burned areas than in nonburned areas, where it is almost nonexistent. Biswell [11] states that seedlings are seldom seen except where there has been fire. Nevertheless, the mortality of Ceanothus spp. seedlings is high during the first 2 postfire years [22]. Environmental factors that affect the growth and survival of these seedlings include insects and other animal browsing, damping-off fungus, soil moisture, exposure, and soil temperature. The first 2 weeks after emergence are the most critical for survival [18].

Asexual regeneration: Layering is common in whitethorn ceanothus at higher elevations where the weight of snow forces branches and stems down to the ground [61]. Stump-sprouting from a lignotuber is also common after the top of the shrub is damaged [40,50].

  • 10. Biswell, H. H.; Buchanan, H.; Gibbens, R. P. 1966. Ecology of the vegetation of a second-growth sequoia forest. Ecology. 47(4): 630-634. [55065]
  • 11. Biswell, Harold H. 1974. Effects of fire on chaparral. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 321-364. [14542]
  • 17. Buchanan, Hayle; Biswell, Harold H.; Gibbens, Robert P. 1966. Succession of vegetation in a cut-over Sierra redwood forest. Utah Academy Proceedings. 43(Part 1): 43-48. [16543]
  • 18. Bullock, Scarlett. 1982. Reproductive ecology of Ceanothus cordulatus. Fresno, CA: California State University. 66 p. Thesis. [61470]
  • 22. Conard, Susan G.; Jaramillo, Annabelle E.; Cromack, Kermit, Jr.; Rose, Sharon, compilers. 1985. The role of the genus Ceanothus in western forest ecosystems. Gen. Tech. Rep. PNW-182. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 72 p. [668]
  • 37. Gratkowski, H. 1961. Brush seedlings after controlled burning of brushlands in southwestern Oregon. Journal of Forestry. 59(12): 885-888. [3392]
  • 38. Gratkowski, H. 1974. Origin of mountain whitethorn brushfields on burns and cuttings in Pacific Northwest forests. Proceedings of the Western Society of Weed Science. 27: 5-8. [4898]
  • 40. Gratkowski, H. 1978. Herbicides for shrub and weed control in western Oregon. Gen. Tech. Rep. PNW-77. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 48 p. [6539]
  • 48. Hobbs, Stephen D.; Radosevich, Steven R. 1987. Nonchemical control of evergreen hardwood competition in new conifer plantations. In: Plumb, Timothy R.; Pillsbury, Norman H., technical coordinators. Proceedings of the symposium on multiple-use management of California's hardwood resources; 1986 November 12-14; San Luis Obispo, CA. Gen. Tech. Rep. PSW-100. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 114-121. [5365]
  • 50. James, Susanne. 1984. Lignotubers and burls--their structure, function and ecological significance in Mediterranean ecosystems. Botanical Review. 50(3): 225-266. [5590]
  • 52. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 2 volumes]. Dissertation. [42426]
  • 53. Kauffman, J. B.; Martin, R. E. 1990. Sprouting shrub response to different seasons and fuel consumption levels of prescribed fire in Sierra Nevada mixed conifer ecosystems. Forest Science. 36(3): 748-764. [13063]
  • 54. Kauffman, John Boone. 1986. The ecological response of the shrub component to prescribed burning in mixed conifer ecosystems. Berkeley, CA: University of California, Berkeley. 235 p. Dissertation. [19559]
  • 55. Keeley, Jon E. 1991. Seed germination and life history syndromes in the California chaparral. The Botanical Review. 57(2): 81-116. [36973]
  • 61. Kozlowski, T. T. 2002. Physiological ecology of natural regeneration of harvested and disturbed forest stands: implications for forest management. Forest Ecology and Management. 158(1-3): 195-221. [42122]
  • 67. McArthur, E. Durant. 1989. Breeding systems in shrubs. In: McKell, Cyrus M., ed. The biology and utilization of shrubs. San Diego, CA: Academic Press, Inc.: 341-361. [8039]
  • 68. McDonald, Philip M. 1981. Adaptations of woody shrubs. In: Hobbs, S. D.; Helgerson, O. T., eds. Reforestation of skeletal soils: Proceedings of a workshop; 1981 November 17-19; Medford, OR. Corvallis, OR: Oregon State University, Forest Research Laboratory: 21-29. [4979]
  • 80. Quick, Clarence R. 1935. Notes on the germination of ceanothus seeds. Madrono. 3: 135-140. [4135]
  • 82. Quick, Clarence R.; Quick, Alice S. 1961. Germination of ceanothus seeds. Madrono. 16: 23-30. [4134]
  • 86. Schimke, Harry E.; Green, Lisle R. 1970. Prescribed fire for maintaining fuel-breaks in the central Sierra Nevada. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 9 p. [11189]

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Growth Form (according to Raunkiær Life-form classification)

More info on this topic.

More info for the term: phanerophyte

RAUNKIAER [83] LIFE FORM:
Phanerophyte
  • 83. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843]

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Life Form

More info for the term: shrub

Shrub

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Life History and Behavior

Cyclicity

Phenology

More info on this topic.

Seasonal development of whitethorn ceanothus begins with emergence and extends through a growing season ranging from 75 to 95 days depending on emergence date and elevation at which it is found. Germination of seedlings begins in late May and June, and they are usually well established by 4 weeks of age. The seedlings were observed to grow at a rate of 0.2 inches (0.5 cm) per week until late August when they began to go dormant. After the 1st growing season whitethorn ceanothus grow very rapidly. In mature whitethorn ceanothus new growth and flower bud swelling occur at the same time, ranging from late May to mid-June depending on elevation. Blossoming is expected about 10 days later and continues for approximately 23 days [18].

Whitethorn ceanothus flowers between May and August dependent on where location [23,52,74,78]. Seed maturity is reached in the late summer, generally in August or September.

  • 18. Bullock, Scarlett. 1982. Reproductive ecology of Ceanothus cordulatus. Fresno, CA: California State University. 66 p. Thesis. [61470]
  • 23. Conard, Susan G.; Reed, Merton J. 2003. Ceanothus L. ceanothus, [Online]. In: Bonner, Franklin T., tech. coord. Woody plant seed manual. Washington, DC: U.S. Department of Agriculture, National Tree Seed Laboratory (Producer). Available: http://www.nsl.fs.fed.us/wpsm/index.html [2006, May 3]. [62009]
  • 52. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 2 volumes]. Dissertation. [42426]
  • 74. Munz, Philip A. 1974. A flora of southern California. Berkeley, CA: University of California Press. 1086 p. [4924]
  • 78. Post, R. L. 1989. Mountain whitethorn (Ceanothus cordulatus). Fact Sheet 89-64. Reno, NV: University of Nevada, College of Agriculture, Nevada Cooperative Extension. 2p. [60460]

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Molecular Biology and Genetics

Molecular Biology

Barcode data: Ceanothus cordulatus

The following is a representative barcode sequence, the centroid of all available sequences for this species.


Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Statistics of barcoding coverage: Ceanothus cordulatus

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Specimens with Barcodes: 2
Species With Barcodes: 1
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Conservation

Conservation Status

National NatureServe Conservation Status

United States

Rounded National Status Rank: NNR - Unranked

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

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NatureServe Conservation Status

Rounded Global Status Rank: G5 - Secure

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

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Status

Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).

Public Domain

USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Threats

Pests and potential problems

Fairly free from diseases, but is susceptible to crown and root problems related to agricultural soils and wet and poorly drained soils.

Public Domain

USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Management

Management considerations

More info for the terms: competition, shrub, tree

There a few main points to consider when managing whitethorn ceanothus. It increases with
disturbance and forms very dense, difficult to penetrate brushfields. It is regarded as a
very strong competitor that can hinder tree seedling growth and subsequent conifer regeneration
[22,57,94]. Whitethorn ceanothus may compete with tree seedlings, but it also provides ongoing
nitrogen that may improve the site for conifer establishment and growth after establishment.
Soil nitrogen, however, probably becomes most important for tree seedlings after they have
cleared the initial hurdle of establishment [49,76]. In the past, herbicide treatments and
allowing livestock grazing in whitethorn ceanothus brushfields were used as management options
to open the dense shrub canopy. This increased the amount of light reaching the young conifers in
the understory and decreased brush competition for soil moisture and nutrients. Initial applications
of herbicide resulted in 100% top kill and 20% whitethorn ceanothus mortality with plant mortality
reaching 90% after the 3rd application [35,39,40,43,92,103]. A study done by Hobbs and Radosevich
[48] concluded that the control of evergreen woody species such as whitethorn ceanothus in young
conifer plantations improved tree seedling growth and in some cases survival.

Conversely, whitethorn ceanothus is valuable as a browse species and if populations decrease,
the amount of available forage for wildlife and livestock is also decreased [57]. Prescribed
burns are often used in land management to encourage the establishment of whitethorn ceanothus
because of its importance as a browse species [27]. It is also beneficial as a nurse plant for
conifer and Sierra gooseberry seedlings, providing shade and available nitrogen [81].

Tappeiner [95] reported the average size of open-grown whitethorn ceanothus plants on ungrazed,
9-year-old tree plantations in the Sierra Nevada and Klamath Mountains. Average crown diameter
was 5.7 feet (1.7 m) and average height was 3.2 feet (.98 m). This information may be useful in
predicting shrub development.
  • 103. Washington State Cooperative Extension Service. 1982. Herbicides in forestry. Pullman, WA: Washington State University, College of Agriculture, Cooperative Extension Service. 13 p. [7873]
  • 22. Conard, Susan G.; Jaramillo, Annabelle E.; Cromack, Kermit, Jr.; Rose, Sharon, compilers. 1985. The role of the genus Ceanothus in western forest ecosystems. Gen. Tech. Rep. PNW-182. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 72 p. [668]
  • 27. Eberlein, Gary P. 1982. Estimating growth of young mountain whitethorn shrubs. PSW-357. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 3 p. [6351]
  • 35. Gratkowski, H. J.; Philbrick, J. R. 1965. Repeated aerial spraying and burning to control sclerophyllous brush. Journal of Forestry. 63(12): 919-923. [8797]
  • 39. Gratkowski, H. 1975. Silvicultural use of herbicides in Pacific Northwest forests. Gen. Tech. Rep. PNW-37. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 44 p. [10998]
  • 40. Gratkowski, H. 1978. Herbicides for shrub and weed control in western Oregon. Gen. Tech. Rep. PNW-77. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 48 p. [6539]
  • 43. Greiman, Harley L. 1988. Sheep grazing in conifer plantations. Rangelands. 10(3): 99-101. [5411]
  • 48. Hobbs, Stephen D.; Radosevich, Steven R. 1987. Nonchemical control of evergreen hardwood competition in new conifer plantations. In: Plumb, Timothy R.; Pillsbury, Norman H., technical coordinators. Proceedings of the symposium on multiple-use management of California's hardwood resources; 1986 November 12-14; San Luis Obispo, CA. Gen. Tech. Rep. PSW-100. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 114-121. [5365]
  • 49. Husari, Susan. 1980. Fire ecology of the vegetative habitat types in the Lassen Fire Management Planning Area. In: Swanson, John R.; Johnson, Robert C.; Merrifield, Dave; Dennestan, Alan, compilers. Lassen Fire Management Planning Area: Lassen Volcanic National Park-Caribou Wilderness Unit. Mineral, CA: U.S. Department of the Interior, National Park Service, Lassen Volcanic National Park; Susanville, CA: U.S. Department of Agriculture, Forest Service, Lassen National Forest: Appendix 3: 1-23. [21408]
  • 57. Kie, John G. 1985. Production of deerbrush and mountain whitethorn related to shrub volume and overstory crown closure. Res. Note PSW-377. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 4 p. [4835]
  • 76. Oakley, Brian B.; North, Malcolm P.; Franklin, Jerry F. 2003. The effects of fire on soil nitrogen associated with patches of the actinorhizal shrub Ceanothus cordulatus. Plant and Soil. 254: 35-46. [60513]
  • 81. Quick, Clarence R. 1944. Effects of snowbrush on the growth of Sierra gooseberry. Journal of Forestry. 42: 827-832. [11504]
  • 92. Stewart, R. E. 1978. Site preparation. In: Cleary, Brian D.; Greaves, Robert D.; Hermann, Richard K., eds. Regenerating Oregon's forests: A guide for the regeneration forester. Corvallis, OR: Oregon State University Extension Service: 99-129. [7205]
  • 94. Strothmann, R. O.; Roy, Douglass F. 1984. Regeneration of Douglas-fir in the Klamath Mountains Region, California and Oregon. Gen. Tech. Rep. PSW-81. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 35 p. [5640]
  • 95. Tappeiner, John C., II. 1981. Estimating potential hardwoods and shrub cover and plantation development. In: Hobbs, S. D; Helgerson, O. T., eds. Reforestation of skeletal soils: Proceedings of a workshop; 1981 November 17-19; Medford, OR. Corvallis, OR: Oregon State University, Forest Research Laboratory: 97-101. [7151]

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Cultivars, improved and selected materials (and area of origin)

‘Maleza’ Cultivar: This was released by the Lockeford,Plant Materials Center, Lockeford, California in 1989. Maleza mountain whitethorn is well suited for medium to coarse textured, well-drained soils. It is adapted to the Tahoe Basin, but grows well at elevations down to 3500 feet where precipitation is adequate.

Contact your local Natural Resources Conservation Service (formerly Soil Conservation Service) office for more information. Look in the phone book under ”United States Government.” The Natural Resources Conservation Service will be listed under the subheading “Department of Agriculture.”

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USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Seed production

Mountain whitethorn seeds mature in late August and September. The seeds are contained within a triangular capsule. Collected capsules should be stored in paper bags and allowed to dry until they open and reveal the seeds.

The seed has a hard exterior coat and therefore a combination of soaking in hot water and cold storage pretreatments are necessary. Seeds should be placed in hot water, preheated to 180 degrees F., and then allowed to cool and soak for 24 hours. Following this hot water treatment, mix the seed with moist sand, place the mixture in plastic bags and store in the refrigerator.

Periodically check the bags for moisture and for swelling of the seed which indicates that they are close to germinating. Once the seeds have swollen, plant them in containers of potting soil and cover them with approximately ½ inch of soil.

After the plants have formed a third pair of leaves they can be transplanted individually to larger ½ to 1 gallon containers. The young plants will be ready for their permanent location in 1 ½ to 2 years. New plants should be watered occasionally until they are well established. Afterward, deep watering every 1 to 1 ½ months will be adequate to maintain uniform growth.

Container grown plants may be available from local nurseries. Dig a hole two to three times the diameter of the root ball and at least six inches deeper. Backfill the hole with six inches of native soil. Make a few, 1/8 inch deep vertical cuts in the root ball, or carefully “tease” roots away from the root ball with your hands to encourage roots to grow into the new soil. Set the plant into the hole and fill in around the roots, firming the soil with your hands as you fill, until the hole is half full. Fill the hole with water and allow it to settle. This will settle the silt and eliminate air pockets around the roots.

Backfill with enough planting mix so the plant will set at the same level it was growing at in the container. Water to allow soil to settle, then add more soil if necessary. Build a berm of soil to form a watering basin around the outer edge of the hole. Break the basin down after two or three years.

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USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Relevance to Humans and Ecosystems

Benefits

Importance to Livestock and Wildlife

More info for the terms: cover, shrub

Whitethorn ceanothus is an important browse producer for wildlife species [10]. It is a major component of the diet of mule deer in the summer ranges of the Sierra Nevada and is also used by cattle on summer grazing allotments [9,17,27,49,57,58,85]. Gordon [34] suggests that the spine-tipped branchlets that develop after establishment may make the shrub less desirable to deer as a browse component. Whitethorn ceanothus is also browsed by bighorn sheep, goats, and domestic sheep [22,25]. Long-eared chipmunks collect and cache the seeds of whitethorn ceanothus [41,97]. High amounts of whitethorn ceanothus are eaten by pocket gophers in California [96]. The fruit of the shrub is eaten by birds and small mammals [25]. Whitethorn ceanothus also provides forage and nesting habitat for the dusky woodrat and part of the diet of the mountain pocket gopher [105]. Whitethorn ceanothus is a host plant for the Great Basin tent caterpillar [20].

Palatability/nutritional value: Whitethorn ceanothus is an important browse species for deer because of its high crude protein content and palatability [9,22,25,49]. It does not, however, provide sufficient nutrients for optimum growth and development in mule deer and is more valuable when consumed along with other species [58]. It is considered as a poor to fair browse species for livestock such as cattle, domestic sheep, and goats [22,25,73].

Cover value: No information is available on this topic.

  • 10. Biswell, H. H.; Buchanan, H.; Gibbens, R. P. 1966. Ecology of the vegetation of a second-growth sequoia forest. Ecology. 47(4): 630-634. [55065]
  • 105. Williams, Daniel F.; Verner, Jared; Sakal, Howard F.; Waters, Jeffrey R. 1992. General biology of major prey species of the California spotted owl. In: Verner, Jared; McKelvey, Kevin S.; Noon, Barry R.; Gutierrez, R. J.; Gould, Gordon I., Jr.; Beck, Thomas W., tech. coords. The California spotted owl: a technical assessment of its current status. Gen. Tech. Rep. PSW-GTR-133. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 207-221. [28203]
  • 17. Buchanan, Hayle; Biswell, Harold H.; Gibbens, Robert P. 1966. Succession of vegetation in a cut-over Sierra redwood forest. Utah Academy Proceedings. 43(Part 1): 43-48. [16543]
  • 20. Clark, Edwin C. 1955. Observations on the ecology of a polyhedrosis of the Great Basin tent caterpillar Malacosoma fragilis. Ecology. 36(3): 373-376. [55064]
  • 22. Conard, Susan G.; Jaramillo, Annabelle E.; Cromack, Kermit, Jr.; Rose, Sharon, compilers. 1985. The role of the genus Ceanothus in western forest ecosystems. Gen. Tech. Rep. PNW-182. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 72 p. [668]
  • 25. Conrad, C. Eugene. 1987. Common shrubs of chaparral and associated ecosystems of southern California. Gen. Tech. Rep. PSW-99. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 86 p. [4209]
  • 27. Eberlein, Gary P. 1982. Estimating growth of young mountain whitethorn shrubs. PSW-357. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 3 p. [6351]
  • 34. Gordon, Donald T. 1970. Natural regeneration of white and red fir...influence of several factors. Research Paper PSW-58. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 32 p. [12462]
  • 41. Gratkowski, Henry John. 1962. Heat as a factor in germination of seeds of Ceanothus velutinus var. laevigatus T. & G. Corvallis, OR: Oregon State University. 122 p. Dissertation. [34941]
  • 49. Husari, Susan. 1980. Fire ecology of the vegetative habitat types in the Lassen Fire Management Planning Area. In: Swanson, John R.; Johnson, Robert C.; Merrifield, Dave; Dennestan, Alan, compilers. Lassen Fire Management Planning Area: Lassen Volcanic National Park-Caribou Wilderness Unit. Mineral, CA: U.S. Department of the Interior, National Park Service, Lassen Volcanic National Park; Susanville, CA: U.S. Department of Agriculture, Forest Service, Lassen National Forest: Appendix 3: 1-23. [21408]
  • 57. Kie, John G. 1985. Production of deerbrush and mountain whitethorn related to shrub volume and overstory crown closure. Res. Note PSW-377. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 4 p. [4835]
  • 58. Kie, John G. 1986. Nutritive quality of Ceanothus shrubs in California mixed conifer forest. Journal of Range Management. 39(6): 521-526. [4071]
  • 73. Mozingo, Hugh N. 1987. Shrubs of the Great Basin: A natural history. Reno, NV: University of Nevada Press. 342 p. [1702]
  • 85. Robinson, Cyril S. 1937. Plants eaten by California mule deer on the Los Padres National Forest. Journal of Forestry. 35(3): 285-292. [51853]
  • 9. Bissell, Harold D.; Strong, Helen. 1955. The crude protein variations in the browse diet of California deer. California Fish and Game. 41(2): 145-155. [10524]
  • 96. Teipner, Cynthia Lea; Garton, Edward O.; Nelson, Lewis, Jr. 1983. Pocket gophers in forest ecosystems. Gen. Tech. Rep. INT-154. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 53 p. [20012]
  • 97. Tevis, Lloyd, Jr. 1952. Autumn foods of chipmunks and golden-mantled ground squirrels in the northern Sierra Nevada. Journal of Mammalogy. 33(2): 198-205. [54672]

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Value for rehabilitation of disturbed sites

Whitethorn ceanothus has considerable value when used for site amelioration. It is used for erosion control on slopes, terraces, and steep banks [78,89,90]. Whitethorn ceanothus is very important for rehabilitation because of nitrogen-fixing and other soil-building attributes. It is tolerant of severe sites and can play a soil building role on these sites [22,49]. It has successfully been used for these purposes in the Lake Tahoe Basin and Lost Canyon, California [15,19,89,90].

A list of available/potential seed sources can be acquired in the USDA, NRCS Commercial Sources of Conservation Plant Material, available online [99].

  • 15. Bowcutt, Frederica. 1990. Native herbaceous species used in mitigation project in Lake Tahoe basin. Restoration & Management Notes. 8(1): 38. [13778]
  • 19. Chan, Franklin J.; Wong, Raymond M. 1989. Reestablishment of native riparian species at an altered high elevation site. In: Abell, Dana L., technical coordinator. Proceedings of the California riparian systems conference: Protection, management, and restoration for the 1990's; 1988 September 22-24; Davis, CA. Gen. Tech. Rep. PSW-110. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 428-435. [13771]
  • 22. Conard, Susan G.; Jaramillo, Annabelle E.; Cromack, Kermit, Jr.; Rose, Sharon, compilers. 1985. The role of the genus Ceanothus in western forest ecosystems. Gen. Tech. Rep. PNW-182. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 72 p. [668]
  • 49. Husari, Susan. 1980. Fire ecology of the vegetative habitat types in the Lassen Fire Management Planning Area. In: Swanson, John R.; Johnson, Robert C.; Merrifield, Dave; Dennestan, Alan, compilers. Lassen Fire Management Planning Area: Lassen Volcanic National Park-Caribou Wilderness Unit. Mineral, CA: U.S. Department of the Interior, National Park Service, Lassen Volcanic National Park; Susanville, CA: U.S. Department of Agriculture, Forest Service, Lassen National Forest: Appendix 3: 1-23. [21408]
  • 78. Post, R. L. 1989. Mountain whitethorn (Ceanothus cordulatus). Fact Sheet 89-64. Reno, NV: University of Nevada, College of Agriculture, Nevada Cooperative Extension. 2p. [60460]
  • 89. Slayback, Robert D. 1987. Vegetative solutions to erosion control in the Tahoe Basin (California). Restoration & Management Notes. 5(2): 102-103. [3780]
  • 90. Slayback, Robert D.; Clary, Raymond F., Jr. 1988. Vegetative solutions to erosion control in the Tahoe Basin. In: Rieger, John P.; Williams, Bradford K., eds. Proceedings of the second native plant revegetation symposium; 1987 April 15-18; San Diego, CA. Madison, WI: University of Wisconsin Arboretum, Society for Ecological Restoration & Management: 66-69. [4097]
  • 99. U.S. Department of Agriculture, Natural Resources Conservation Service, Tucson Plant Materials Center. 2001. Commercial sources of conservation plant materials, [Online]. Available: http://plant-materials.nrcs.usda.gov/pubs/azpmsarseedlist0501.pdf [2003, August 25]. [44989]

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Uses

Mountain whitethorn can be used for ground cover on slopes, terraces or steep banks and as a barrier plant. Mountain whitethorn may be allowed to assume natural forms or may be shaped through pruning and pinching off the growing tips.

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USDA NRCS California State Office and Lockeford Plant Materials Center, California

Source: USDA NRCS PLANTS Database

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Wikipedia

Ceanothus cordulatus

Ceanothus cordulatus is a species of shrub in the buckthorn family Rhamnaceae known by the common names mountain whitethorn and whitethorn ceanothus. It is native to California and adjacent sections of Oregon, Nevada, and Baja California, where it grows on mountain ridges and other forested areas. This is a spreading shrub growing usually wider than tall and up to about 1.5 meters. The stems are gray, with the twigs yellow-green in color and fuzzy in texture when new. The evergreen leaves are alternately arranged and up to 3 centimeters long. Each is oval in shape with three ribs and generally not toothed. The leaves may be hairy or not. The inflorescence is panicle-shaped, up to about 4 centimeters long. The flowers are white to off-white with five sepals and five petals. The fruit is a rough, ridged capsule up to half a centimeter long. It has three valves inside, each containing a seed.

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Names and Taxonomy

Taxonomy

The scientific name of whitethorn ceanothus is Ceanothus cordulatus Kellogg (Rhamnaceae) [51]. Intrasectional hybridization within Ceanothus species is common [67]. When information
specific to whitethorn ceanothus is not available, references will be made to the genus Ceanothus.
  • 51. Kartesz, John T.; Meacham, Christopher A. 1999. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Available: North Carolina Botanical Garden. In cooperation with: The Nature Conservancy, Natural Resources Conservation Service, and U.S. Fish and Wildlife Service [2001, January 16]. [36715]
  • 67. McArthur, E. Durant. 1989. Breeding systems in shrubs. In: McKell, Cyrus M., ed. The biology and utilization of shrubs. San Diego, CA: Academic Press, Inc.: 341-361. [8039]

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Common Names

whitethorn ceanothus

mountain whitethorn

snow bush

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