General: Flax Family (Linaceae). Linum perenne is introduced from Eurasia. Linum lewisii is a comparable U.S. native plant (figure 1). In general, flax is an annual or short-lived, semi-evergreen perennial forb, sometimes semi-woody at base with attractive flowers ranging from white to blue to yellow to red in color. Common in the western United States, blue flax is considered a woody subshrub in the PLANTS database (USDA, NRCS 2000). According to Cronquist et al. (1997), “the only significant difference between Linum lewisii and the Eurasian Linum perenne appears to be that the former is homostylic, and the latter heterostylic.”
Flax plants have many narrow, small, alternate (rarely opposite), simple and entire leaves that are sessile (lacking stalks) on the stems. The perfect and regular, generally showy flowers are borne in racemes or cymes. The sepals, petals, and stamens are five, the fruit a capsule, and the seeds in most species are mucilaginous when wet.
Regularity: Regularly occurring
Regularity: Regularly occurring
States or Provinces
Regional Distribution in the Western United States
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 :
1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
7 Lower Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
Flax species do best on well-drained soils. Most ecotypes do well on infertile, disturbed soils. They have excellent cold winter and drought tolerance. They will tolerate weakly saline to weakly acidic sites. Plants are usually found in open areas, but will tolerate semi-shaded conditions. They are fire resistant due to leaves and stems staying green with relatively high moisture content during most of the fire season.
Lewis flax can be found from Alaska to California and east to Minnesota in mixed grass, sagebrush, shadscale, piñon-juniper, mountain brush and aspen communities and in openings in coniferous forests. Blue flax is native to Eurasia and has been planted successfully throughout the United States. For current distribution, consult the Plant Profile page for this species on the PLANTS Web site.
Lewis flax is a native, semievergreen, perennial forb. It has several glabrous, erect stems (8 to 28 inches (20-70 cm) tall) arising from a persistent, branched caudex and taproot [61,63]. The leaves are numerous, alternate, linear to lanceolate, and glabrous. Flowers are borne on a leafy, 1-sided raceme. Flowers open at sunrise and petals fall by noon [4,121]. The capsule is ovoid to globose, splitting from the top downward into ten 1-seeded segments [33,59,68,122].
Lewis flax occurs on valley bottoms, benches, slopes, ridges, and meadows, from prairie to alpine elevations [64,121]. It grows best in full sunlight and has little to no shade tolerance [61,62,121]. Site descriptions by state are provided below.
|State, Region, Province||Site Characteristics|
|Arizona||open mesas, rocky hills and slopes, and coniferous forests; 3,500 to 9,500 feet (1,100-2,900 m) [69,130]|
|Pima County, Arizona||widely scattered on flats and bajadas; 2,200 to 2,400 feet (670-720 m) |
|California||dry open ridges and slopes; 1,300 to 11,000 feet (400-3,400 m) [59,91]|
|Colorado||plains to upper montane |
|Nevada||washes, cliff basins, mesas to mountain slopes; 4,500 to 9,000 feet (1,400-2,700 m) [16,68]|
|Utah||xeric to mesophytic, gravelly hillsides and montane forest zones; 4,500 to 9,500 feet (1,400-2,900 m) [3,36]|
|Wyoming||plains to alpine |
|Black Hills, South Dakota||plains, hills, and slopes |
|Pacific Northwest||prairies to alpine ridges, usually on dry, well-drained soil |
|Baja California||gravelly soil, margins of meadows, and rocky ridges |
|Neuvo Leon||alpine meadows above 11,000 feet (3,500 m) [15,19]|
Climate: Lewis flax is suitable for sites with average annual precipitation that ranges from 10 to 23 inches (250-580 mm). Vigorous growth can be expected on sites averaging greater than 16 inches (410 mm) [61,121]. Lewis flax seedlings are "excellent competitors" in pinyon-juniper types that average <15 inches (380 mm) annual precipitation and are "medium competitors" on sites that average more than 15 inches (380 mm) annual precipitation. Mature plants are "medium competitors" at both of these precipitation levels .
Soil characteristics for sites that Lewis flax is known to occur on grassland types in North Dakota are as follows :
The little bluestem-needle-and-thread grass-threadleaf sedge (Schizachyrium scoparium-Hesperostipa comata-Carex filifolia) type has soils that are composed of 70% sand, 18% silt, and 12% clay and pH between 7.3 to 8.6. These soils are relatively shallow with parent materials of sandstone, shale, or siltstone frequently within 10 to 20 inches (41-51 cm) of the surface. The needle-and-thread grass-plains muhly (Muhlenbergia cuspidata)-carex (Carex duriuscula and C. filifolia) type has extremely shallow soils with bedrock, gravel, or scoria close to the surface, pH between 7.2 to 8.9, and percentages for sand, silt, and clay are 46, 19, 35, respectively. The big bluestem-porcupine grass-prairie dropseed (Andropogon gerardii-Stipa spartea-Sporobolus heterolepis) occupies shallow soils with an average pH of 7.3. Soils were 64% sand, 24% silt, 15% clay .
Habitat: Rangeland Cover Types
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 terms: cover, shrub
SRM (RANGELAND) COVER TYPES :
101 Bluebunch wheatgrass
102 Idaho fescue
104 Antelope bitterbrush-bluebunch wheatgrass
105 Antelope bitterbrush-Idaho fescue
107 Western juniper/big sagebrush/bluebunch wheatgrass
108 Alpine Idaho fescue
109 Ponderosa pine shrubland
209 Montane shrubland
301 Bluebunch wheatgrass-blue grama
302 Bluebunch wheatgrass-Sandberg bluegrass
303 Bluebunch wheatgrass-western wheatgrass
304 Idaho fescue-bluebunch wheatgrass
309 Idaho fescue-western wheatgrass
310 Needle-and-thread-blue grama
314 Big sagebrush-bluebunch wheatgrass
315 Big sagebrush-Idaho fescue
317 Bitterbrush-bluebunch wheatgrass
318 Bitterbrush-Idaho fescue
320 Black sagebrush-bluebunch wheatgrass
321 Black sagebrush-Idaho fescue
401 Basin big sagebrush
402 Mountain big sagebrush
403 Wyoming big sagebrush
405 Black sagebrush
408 Other sagebrush types
411 Aspen woodland
412 Juniper-pinyon woodland
413 Gambel oak
414 Salt desert shrub
415 Curlleaf mountain-mahogany
416 True mountain-mahogany
504 Juniper-pinyon pine woodland
601 Bluestem prairie
604 Bluestem-grama prairie
611 Blue grama-buffalo grass
614 Crested wheatgrass
704 Blue grama-western wheatgrass
705 Blue grama-galleta
706 Blue grama-sideoats grama
710 Bluestem prairie
715 Grama-buffalo grass
802 Missouri prairie
803 Missouri glades
906 Broadleaf forest
Habitat: Cover Types
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 :
107 White spruce
201 White spruce
202 White spruce-paper birch
203 Balsam poplar
206 Engelmann spruce-subalpine fir
209 Bristlecone pine
210 Interior Douglas-fir
211 White fir
215 Western white pine
218 Lodgepole pine
219 Limber pine
220 Rocky Mountain juniper
229 Pacific Douglas-fir
237 Interior ponderosa pine
238 Western juniper
244 Pacific ponderosa pine-Douglas-fir
245 Pacific ponderosa pine
247 Jeffrey pine
251 White spruce-aspen
Habitat: Plant Associations
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  PLANT ASSOCIATIONS:
K005 Mixed conifer forest
K008 Lodgepole pine-subalpine forest
K009 Pine-cypress forest
K010 Ponderosa shrub forest
K011 Western ponderosa forest
K012 Douglas-fir forest
K016 Eastern ponderosa forest
K017 Black Hills pine forest
K018 Pine-Douglas-fir forest
K019 Arizona pine forest
K020 Spruce-fir-Douglas-fir forest
K021 Southwestern spruce-fir forest
K022 Great Basin pine forest
K023 Juniper-pinyon woodland
K024 Juniper steppe woodland
K031 Oak-juniper woodland
K032 Transition between K031 and K037
K034 Montane chaparral
K037 Mountain-mahogany-oak scrub
K038 Great Basin sagebrush
K052 Alpine meadows and barren
K053 Grama-galleta steppe
K055 Sagebrush steppe
K056 Wheatgrass-needlegrass shrubsteppe
K063 Foothills prairie
K065 Grama-buffalo grass
K068 Wheatgrass-grama-buffalo grass
K069 Bluestem-grama prairie
K074 Bluestem prairie
K075 Nebraska Sandhills prairie
K088 Fayette prairie
K093 Great Lakes spruce-fir forest
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):
FRES21 Ponderosa pine
FRES22 Western white pine
FRES26 Lodgepole pine
FRES30 Desert shrub
FRES32 Texas savanna
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
Key Plant Community Associations
flax alpine community of the White Mountains in California .
Planting: Flax should be seeded with a drill or broadcast at a depth of 1/4 inch or less into a firm seedbed. The ideal seeding depth is 1/8 inch. Flax is not recommended for single species seedings. The full seeding rate (not recommended) for these forbs is 4 pounds Pure Live Seed (PLS) per acre or 24 PLS per square foot. When used as a component of a mix, adjust to percent of mix desired. For mined lands and other harsh critical areas, doubling the seeding rate component of flax is not required.
The best seeding results are obtained from seeding in late fall to very early spring (because of grass component of mix) on heavy to medium textured soils and in late fall on medium to light textured soils. Late summer (August - mid September) seeding is not recommended. Dormant fall seedings (preferred seeding period for flax) will pre-chill seed and reduce seed dormancy which may be present. Mulching, irrigation, and weed control all benefit stand establishment. Seedling vigor is good, but not as good as most grasses. Germination normally occurs the first growing season, but may not occur until the second growing season. Full flowering should not be expected until at least the second growing season.
Stands may require weed control measures during establishment. Because flax is a broadleaf plant, use of 2,4-D is not recommended. Mow weeds at or prior to their bloom stage. Grasshoppers and other insects may also damage new stands and pesticides may be needed.
Fire Management Considerations
Lewis flax maintains its green basal foliage year round and "does not readily burn". These traits may make it useful in vegetative fuel breaks to reduce the spread of fire [57,117]. It is frequently used in greenstripping projects throughout the Intermountain west because of its large ecological amplitude, ability to compete with annual weeds, ease of establishment, low flammability, and resilience and regrowth capabilities [85,95,96].
Postfire seeding with Lewis flax may be a viable postfire management option. Lewis flax appears to establish more readily on burned than unburned microsites following postfire broadcast seeding in meadows dominated by basin big sagebrush. A study done in the Toiyabe Mountains of Nevada measured the response of certain species while managing and restoring basin big sagebrush. The study sites were representative of dry meadow vegetation, and depth to water table was described as wet, intermediate, or dry. Treatment sites were burned and then seeded. Seedling establishment was recorded for each site from the 1st through the 3rd growing season. Lewis flax occurred on the wet and dry sites, but was not recorded on the control or intermediate sites [140,141].
Postfire establishment of Lewis flax seeded onto burned slash pile microsites under ponderosa pine in Arizona appears successful. Piles of slash were burned in February 2000 and subsequently underwent 1 of 5 site amelioration treatments. These treatments were: 1) no treatment; 2) living soil amendment (containing micro-organisms, arbuscular mycorrhizae, and plant propagules); 3) sterilized soil amendment (no propagules); 4) native seed amendment; and 5) seed/soil amendment. Establishment of Lewis flax was significantly higher (P ≤ 0.05) when seeded in conjunction with soil amendment. The average cover of Lewis flax for the native seed and seed/soil amendment plots is detailed below .
|Treatment 4||Treatment 5|
|2000||0.01 Â± 0.01||0.11 Â± 0.04|
|2001||0 Â± 0||0.13 Â± 0.07|
Broad-scale Impacts of Plant Response to Fire
The impacts of fire and herbivory were the focus of a study done in Jasper National Park in Alberta, Canada,
where Lewis flax cover increased 2 years after fire in closed-canopy plots accessible to elk, but was not
significantly different on open-canopy plots or those where elk were excluded. Lewis flax cover in all
treatements averaged less than 1%. Plots were subjected to a low-intensity prescribed fire in May 1999,
with a rate of spread of 2 to 5 m/min and flame lengths of 10 to 20 cm with occasional "candling".
Percent ground cover of Lewis flax is detailed in the table below .
|Closed canopy||Open canopy|
*bold indicates a significant difference between years at P = 0.05
Plant Response to Fire
Lewis flax is likely to survive and sprout from the caudex after fire, although no direct observations of this are reported in the literature.
Anecdotal information provided by Wasser  indicates that Lewis flax may establish from seed after fire. Lewis flax was present on burned sites and not on unburned sites in blackbrush communities in southern Nevada , suggesting that it recovers from an off-site seed source or from soil stored seed. Lewis flax seeds are capable of surviving in the soil for "multiple" years , so it is possible that Lewis flax may recover from the seed bank after fire. However, further research is needed on how Lewis flax seeds respond to fire.
Immediate Effect of Fire
Lewis flax is likely top-killed in the event of high severity fire. Lewis flax maintains some green basal foliage year-round and, according to anecdotal information provided by Stevens and Monsen , "does not readily burn".
POSTFIRE REGENERATION STRATEGY :
Ground residual colonizer (on-site, initial community)
Secondary colonizer (on-site or off-site seed sources)
Fire adaptations: Lewis flax maintains some green basal foliage year round and, according to anecdotal information provided by Stevens and Monsen , "does not readily burn". Information provided by Wasser  indicates that Lewis flax may be killed by fire and that it may establish from seed after fire.
FIRE REGIMES: Lewis flax most commonly occurs in communities that are characterized by short fire-return intervals and mixed-severity or stand-replacement fire types.
The following table provides fire return intervals for plant communities and ecosystems where Lewis flax is important. For further information, see the FEIS review of the dominant species listed below.
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|bluestem prairie||Andropogon gerardii var. gerardii-Schizachyrium scoparium||76,94]|
|Nebraska sandhills prairie||A. gerardii var. paucipilus-Schizachyrium scoparium||94]|
|silver sagebrush steppe||Artemisia cana||5-45 [58,101,139]|
|sagebrush steppe||A. tridentata/Pseudoroegneria spicata||20-70 |
|basin big sagebrush||A. tridentata var. tridentata||12-43 |
|mountain big sagebrush||A. tridentata var. vaseyana||15-40 [7,27,84]|
|Wyoming big sagebrush||A. tridentata var. wyomingensis||10-70 (x=40) [127,142]|
|saltbush-greasewood||Atriplex confertifolia-Sarcobatus vermiculatus||94]|
|plains grasslands||Bouteloua spp.||94,139]|
|blue grama-needle-and-thread grass-western wheatgrass||B. gracilis-Hesperostipa comata-Pascopyrum smithii||94,104,139]|
|blue grama-buffalo grass||B. gracilis-Buchloe dactyloides||94,139]|
|grama-galleta steppe||B. gracilis-Pleuraphis jamesii||94]|
|California montane chaparral||Ceanothus and/or Arctostaphylos spp.||50-100 |
|curlleaf mountain-mahogany*||Cercocarpus ledifolius||13-1,000 [9,107]|
|mountain-mahogany-Gambel oak scrub||C. ledifolius-Quercus gambelii||<35 to <100|
|blackbrush||Coleogyne ramosissima||<35 to <100|
|western juniper||Juniperus occidentalis||20-70|
|Rocky Mountain juniper||J. scopulorum||<35 |
|wheatgrass plains grasslands||Pascopyrum smithii||<5-47+ [94,101,139]|
|Engelmann spruce-subalpine fir||Picea engelmannii-Abies lasiocarpa||35 to >200 |
|pinyon-juniper||Pinus-Juniperus spp.||<35 |
|Rocky Mountain bristlecone pine||P. aristata||9-55 [37,38]|
|Rocky Mountain lodgepole pine*||P. contorta var. latifolia||25-340 [12,13,124]|
|Sierra lodgepole pine*||P. contorta var. murrayana||35-200 |
|Colorado pinyon||P. edulis||10-400+ [48,51,72,94]|
|Jeffrey pine||P. jeffreyi||5-30|
|western white pine*||P. monticola||50-200|
|Pacific ponderosa pine*||P. ponderosa var. ponderosa||1-47 |
|interior ponderosa pine*||P. ponderosa var. scopulorum||2-30 [6,11,80]|
|Arizona pine||P. ponderosa var. arizonica||2-15 [11,31,109]|
|aspen-birch||Populus tremuloides-Betula papyrifera||35-200 [41,128]|
|quaking aspen (west of the Great Plains)||P. tremuloides||7-120 [6,53,83]|
|mountain grasslands||Pseudoroegneria spicata||3-40 (x=10) [5,6]|
|Rocky Mountain Douglas-fir*||Pseudotsuga menziesii var. glauca||25-100 [6,7,8]|
|coastal Douglas-fir*||P. menziesii var. menziesii||40-240 [6,88,103]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||<35 to <200 |
|Fayette prairie||Schizachyrium scoparium-Buchloe dactyloides||<10 |
|little bluestem-grama prairie||S. scoparium-Bouteloua spp.||<35 |
More info for the terms: forbs, frequency
Lewis flax is 1 of the forbs with highest frequency on a 40- to 50-year-old burn in west-central Montana. Douglas-fir, lodgepole pine, and quaking aspen were representative small trees regenerating on this site .
Pollination: Lewis flax is pollinated by flies, bees, and other insects in Colorado [1,70,71]. In western North Dakota populations, bees and flies were the most common visitors . It is also probable that Lewis flax is wind pollinated .
In montane habitats above 9,100 feet (2,800 m) at the Rocky Mountain Biological Laboratory in Colorado, flies were more common than bees as pollinators of Lewis flax. Bees are more effective than flies at depositing pollen, but mean bee visitation of Lewis flax was lowest at the high-elevation site in all years. The lower number of bee visits at higher elevation sites could be because the dilute nectar available from Lewis flax flowers is less attractive than the nectar-rich flowers of other species that occur in alpine areas, or because there is a decrease in the number of solitary bees at high elevations [70,71].
Pollen-eating muscoid flies are common pollinators of Lewis flax in Colorado. One Lewis flax flower produces fewer than 3,500 grains of pollen during the 1-day flowering period. These flies are known to eat more than 1,000 grains in a day and could have a negative impact on plant paternal fitness .
Although Lewis flax is self-compatible, pollination by insects is needed for seed production [70,71]. In her study on the role of fly pollination in montane habitats, Kearns  grew 5 Lewis flax plants under laboratory conditions. The plants received no pollination treatments or insect visits. The 5 plants produced 438 flowers, none of which produced fruits with seeds .
Lewis flax seed set differed significantly (p = 0.0001) among low-, mid-, and high-elevation sites and among years (P = 0.03). Seed set decreased with increasing elevation. The lower seed set at higher elevations could be due to pollen limitation (see Pollination) or could be due to the shorter growing season and extreme weather conditions in alpine areas .
A study of Lewis flax plants transplanted from steppe and forest communities above the Yukon River at Eagle, Alaska indicates that light and water availability affect Lewis flax seed production. Reproducing individuals grown in the shade had an 87% reduction in total seed biomass. An increase in light significantly (P ≤ 0.05) affected seed production. Total seed biomass increased nearly fivefold with added moisture and was significant at the P ≤ 0.01 level .
Seed dispersal: No information is available on this topic.
Seed banking: Seed banking and longevity under field conditions have not been well studied for this species, although Kitchen  suggests that seeds survive for "multiple" years. Evidence of an afterrippening period for Lewis flax seeds (see Germination) suggests that they may remain viable in the soil for extended periods; however, further research is needed on the seed banking capabilities of Lewis flax.
Germination: Many Lewis flax seeds germinate in 10 to 15 days indoors at 60 to 70 Â°F (16-21 Â°C), and in 15 to 30 days in the field, under variable moisture and temperature conditions . Lewis flax seeds taken from a high mountain grassland study site in western Colorado were germinated in a greenhouse setting. The optimum temperature regime for seed germination was 59 Â°F (15 Â°C). The cumulative percentages for Lewis flax seeds that germinated are presented below .
|Cumulative percent germination||16||80||86||86||86|
Duration and climatic conditions of storage affect germination rates of Lewis flax [21,66,74] and suggests that Lewis flax is able to germinate under variable conditions. Jorgensen and Wilson  revealed that Lewis flax seeds germinated in the dark at 34 to 38 Â°F (1.1- 3.3 Â°C), and had a mean germination rate of 55% at ~35 days and 75% at ~55 days. A germination study using Lewis flax seeds from 21 Utah, Idaho, Nevada, and Washington populations found that percent germination for seeds recently harvested was 17% to 100% with no prechill period (control), 28% to 100% for seeds that underwent a 28-day prechill period, and 32% to 100% for those with a 168-day prechill period . These results suggest that average germination of Lewis flax seeds increases the longer they are prechilled. Conversely, greenhouse germination trials revealed that the greatest percent germination of Lewis flax seeds occurred after being stored dry, at room temperature. There was a decrease in percent germination for seeds stored in dry, cold storage and wet, cold storage. The seeds used in the trials were collected during the summer on western North Dakota native ranges. The storage period for all treatments began December 1, and germination tests began on the 10th of each month and were observed for 60 days. The percent germination of Lewis flax seeds is presented below .
|Dry-room temperature storage||16||23||36||33||79|
Lewis flax seeds may have an afterripening period, in that they initially exhibit low germination rates that increase after a period of storage [21,66,74]. Lewis flax germination was recorded, over a 25 year period, for seeds stored in an open, unheated, and uncooled warehouse. Greatest germination occurred after 5 years of storage. Percent germination of Lewis flax seeds after 2 to 25 years of storage in an open warehouse are presented below .
Years of Storage
Seedling establishment/growth: The seed coat of Lewis flax seed is mucilaginous (secretes a gelatinous or gummy substance). The mucilage adheres to the soil when hydrated, resulting in seed retention on site  and allowing for establishment on bare soil. Lewis flax seedlings have a thin, vigorous root, 1/3 to 1/2 the length of the hypocotyl . Seedlings are vigorous, and have a rapid growth rate .
Leachates from singleleaf pinyon (Pinus monophylla) and Utah juniper (Juniperus osteosperma) litter may inhibit Lewis flax seedling establishment. In a greenhouse study, buried seeds emerged more frequently from mineral soil than from pots with singleleaf pinyon and Utah juniper litter. When Lewis flax seeds were broadcast seeded, emergence was greater on singleleaf pinyon litter than on either Utah juniper litter or mineral soil . Everett  speculates that allelopathic effects of pinyon litter on broadcast seeds are offset by improved surface microenvironment and reduced seed desiccation.
A seedling establishment study done in southwestern Colorado's San Juan Basin Research Center reports that Lewis flax seedlings have a better chance of establishing if seeds are planted in fall rather than spring. Three separate plantings were done in April, May, and October of the 1st year, and in May, June, and October of the 2nd year. Establishment ratings were assigned to the stands based on visual observations made in May of the following year. Lewis flax seedling establishment was higher for October plantings than spring plantings in both years. Establishment ratings are summarized below .
|Date of planting||Establishment rating*|
4=75% to 100% of complete stand (12 plants/m of row)
Asexual regeneration: Lewis flax sprouts from the caudex .
Growth Form (according to Raunkiær Life-form classification)
More info for the term: hemicryptophyte
RAUNKIAER  LIFE FORM:
Life History and Behavior
Lewis flax normally requires 2 to 3 years to establish, mature, and flower . Wasser  states that it might begin to flower by the 3rd year or, under more favorable conditions, by the end of the 2nd. Lewis flax maintains some green basal foliage year-round .
Lewis flax flowering periods were studied for 8 years in Saskatchewan. The mean first-flower date was June 5. The earliest flower date was May 19 and the latest was June 19. The latest date a plant was in flower was recorded as July 27. The mean flowering period was 33 days . The following table provides flowering dates for Lewis flax.
|State, Region, Province||Anthesis Period|
|Arizona||March to September |
|California||May to September |
|Nevada||April to August [16,68]|
|West Virginia||June and July |
|Baja California||March to September |
|Pacific Northwest||May to July |
|Canada||late May |
Lewis flax seeds mature in late July and August .
Molecular Biology and Genetics
Barcode data: Linum lewisii
Statistics of barcoding coverage: Linum lewisii
Public Records: 7
Specimens with Barcodes: 13
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status and wetland indicator values.
An important aspect in management considerations for Lewis flax is its tolerance
of disturbance from grazing and herbicide applications.
Grazing: Lewis flax can survive heavy grazing
after it is established  and in most cases is an increaser . Two pastures on mixed prairie grassland
near Fort Collins, Colorado were studied to find effects of 2 different management systems: deferred rotation
grazing and continuous grazing. The findings are summarized below .
|Number of quadrats in which Lewis flax occurred||Total number of Lewis flax individuals|
|Deferred Rotation Pasture||2||2|
|Continuously Grazed Pasture||6||22|
A floristic inventory was conducted on 4 heavily used black-tailed prairie dog towns in Billings County,
North Dakota. Horses, cattle, and native ungulates contributed to the high level of disturbance in these
areas. The presence of Lewis flax was recorded on 1 of 4 prairie dog towns, confirming its ability to
survive in highly disturbed areas .
Research on an Idaho fescue-bluebunch wheatgrass grassland in southwestern Montana suggests that Lewis
flax survives under a variety of grazing regimes. Lewis flax cover in ungrazed, lightly grazed, and heavily
grazed sites ranged from 0 to 2.1 cmÂ²/0.1mÂ². No statistically significant differences were reported .
Lewis flax was listed as an indicator for range readiness in the Swift Current district, Saskatchewan:
"range will be ready to graze when the plants commence blooming" .
Herbicide: In a study done on the effects of 2, 4-D on forbs
and shrubs associated with big sagebrush in Idaho, Lewis flax was unharmed by applications of 2, 4-D .
Cultivars, improved and selected materials (and area of origin)
Foundation and registered seed is available for each variety through the appropriate state Crop Improvement Association or commercial sources to grow certified seed.
'Appar' blue flax (Linum perenne) is a selected release from seed originally collected in the Black Hills of South Dakota. 'Appar' was selected by the Forest Service Forest and Range Experiment Station and Aberdeen Plant Materials Center for outstanding vigor, beauty, and competitiveness with grasses prevalent on sites where it was collected. The Natural Resources Conservation Service, University of Idaho Agricultural Experiment Station, Utah Division of Wildlife Resources, and the Forest Service Forest and Range Experiment Station released 'Appar' in 1980. 'Appar' was released as native flax (Linum lewisii), but was later determined to be a naturalized introduced species from European origins. 'Appar' was named in honor of A. Perry Plumber, Forest Service (retired) who collected the original material. 'Appar' is a hardy, relatively short-lived, introduced perennial forb, 12 to 36 inches tall, with deep blue flowers that bloom profusely for about six weeks beginning in mid May. It is well adapted to sunny open slopes, well-drained soils from moderately basic to weakly acidic, 10 to 18 inch rainfall areas, at 1,000 to 6,000 feet elevation. It has some shade tolerance, but is not tolerant of poor drainage, flooding, or high water tables. It does well seeded in mixtures with other species. Its intended uses are erosion control, reclamation, highway right-of-ways, homes, gardens, parks, diversity, and beautification. Certified seed is readily available through commercial sources and breeder seed is maintained by Aberdeen Plant Materials Center.
Maple Grove Germplasm Lewis flax (Linum lewisii) is a recent (2003) Selected class Germplasm release of a native collection from the Maple Grove, Utah area. Maple Grove was selected by the Forest Service Forest and Range Experiment Station and Aberdeen Plant Materials Center for outstanding vigor, beauty, and competitiveness with grasses prevalent on sites where it was collected. The Natural Resources Conservation Service, University of Idaho Agricultural Experiment Station, Utah Division of Wildlife Resources, and the Forest Service Forest and Range Experiment Station released Maple Grove in 2003. Maple Grove is a hardy, relatively short-lived, native perennial forb, 12 to 36 inches tall, with light blue flowers that bloom profusely for about six weeks beginning in mid May. It is well adapted to sunny open slopes, well-drained soils from moderately basic to weakly acidic, 10 to 18 inch rainfall areas, at 1,000 to 6,000 feet elevation. It has some shade tolerance, but is not tolerant of poor drainage, flooding, or high water tables. It does well seeded in mixtures with other species. Its intended uses are erosion control, reclamation, highway right-of-ways, homes, gardens, parks, diversity, and beautification. Certified seed is available through the University of Idaho Foundation Seed Program and Utah Crop Improvement Associations and Soil Conservation Districts in Idaho, Utah and Nevada. Certification of seed shall be limited to not more than two generations from the G3 seed.
There are numerous flax species native to the U.S. that may be available through native plant nurseries and seed companies. These include the following: Linum alatum (TX & LA), Linum arenicola (FL), Linum aristatum (UT & AZ to TX), Linum berlandieri (CO to LA), Linum catharticum (northeast US), Linum compactum (MT & ND to NM & TX), Linum intercursum (Atlantic states), Linum lewisii (central & west US), Linum medium (east & central US), and Linum virginianum (east & midwest US). Please check the PLANTS database for other native flax species.
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.”
Flax should be seeded in 24 inch rows at the rate of 2.5 pounds PLS per acre or 36 inch rows at the rate of 1.5 pounds PLS per acre (25 to 30 seeds per linear foot of row) to allow mechanical weed control. It should be seeded in early spring (April - May).
Hand rouging within row and cultivation between rows may be required. Split applications of nitrogen in spring and fall and application of phosphorus in fall will enhance production. For optimum production, do not stress plants for moisture during late bud stage, pollination and re-growth.
Seed is generally harvested in late July to mid-August by wind-rowing before seed shatter and combining with pickup attachment once green stems have dried. Seed is mature when capsules are dry and seed is hard and dark in color. Flowering is indeterminate with mature capsules and the possibility of some flowers present at harvest period. Some seed will shatter once capsules open. Seed should be allowed to dry to 12 (bins) to 15 (sacks) percent moisture and then stored in a cool dry area. Seed retains viability for several years under these conditions.
Seed yields of 600 to 700 pounds per acre of blue flax can be expected under irrigated conditions and 200 to 300 pounds per acre under dryland conditions.
Seed yields of Lewis flax from irrigated fields average 300 to 350 pounds per acre. Seed production of Lewis flax under dryland conditions is not recommended below 16 inches of average annual rainfall.
Growth of flax begins in early spring and flowers appear in mid May through early July depending on species. Weed control and removal of very competitive species may improve chance of establishment. Damage from wildlife and rodents may occur and they may need to be controlled. Disease problems are minimal with flax; however fungus problems have been noted for some native species.
Environmental Concerns: Flax species establish relatively quickly and easily via seed under favorable climatic conditions. They are not rhizomatous or considered "weedy" or invasive species, but could spread into adjoining vegetative communities under ideal climatic and environmental conditions. They coexist with other species and add biodiversity to those plant communities. ‘Appar’ blue flax seed normally germinates the first growing season following planting under favorable temperatures if moisture is available and it generally does not maintain a viable seed-bank. Native flax accessions tested maintain a portion of seed, which does not germinate the first growing season, as a viable seed-bank.
Relevance to Humans and Ecosystems
Other uses and values
Lewis flax was an important plant used by Native Americans. The strong fibers from the stem were made into cords and strings and used in baskets, mats, meshes of snowshoes, and in the weaving of fishing nets. Lewis flax seeds were used in cooking, as they have a pleasant taste and are highly nutritious. Stems were steeped for stomach disorders and roots steeped for eye medicine. The whole plant was also used to make an eye medicine by mashing and soaking it in cold water. Poultices of the crushed fresh leaves were used to reduce swellings, especially for goiter and for gall trouble. Early settlers made a poultice of the powdered seed, corn meal, and boiling water, mixing this into a paste for infected wounds and mumps [123,125].
Value for rehabilitation of disturbed sites
Lewis flax is commercially grown and planted throughout the Intermountain West . It is used in the reclamation of mining sites and spoils, roadsides, and construction sites [23,25,34,61,62,108]. Germination of Lewis flax seeds directly seeded into coal mine spoils at Dickenson, North Dakota was successful, and resulted in 43 seedlings/mÂ² after 120 days. This is a low number, however, compared to other species that had over 300 seedlings/mÂ² . Another reclamation study on coal mine spoils in North Dakota groups Lewis flax with plants described as "showing excellent establishment characteristics, even though they did not make outstanding height growth or provide exceptionally good cover." It was also noted that Lewis flax "appeared to show little promise because of low germination and/or survival for use in revegetation trials on spoil bank material" .
Lewis flax is a desirable species to seed for rehabilitation of rangelands and shrublands [85,129]. Transplanting Lewis flax is usually very successful and establishment can be expected when proper transplanting techniques are used . In arid climate landscapes, the heat/drought-tolerant Lewis flax can be a substitute for plants that require more water . Its ease of establishment is noted as "excellent" . However, because Lewis flax seeds are eaten by deer mice in some vegetation types, they may not be appropriate to use in seed mixes. Everett, Meeuwig, and Stevens  suggest not using highly preferred seeds in some seed mixes, planting desirable species whose seeds are not preferred by deer mice, or treating desirable seeds with a repellent.
Nonnative Species: Lewis flax is a strong competitor against spotted knapweed (Centaurea maculosa). A common garden experiment at The University of Montana Diettert Experimental Gardens in Missoula, Montana, revealed that aboveground biomass of spotted knapweed was lower (~1 g) when planted with Lewis flax versus spotted knapweed grown alone (~4.5 g). Fungicide added to the soil did not affect Lewis flax growth or how Lewis flax interacted with spotted knapweed .
When seeded in mixtures into cheatgrass (Bromus tectorum)-dominated communities, Lewis flax establishes and spreads quickly, occupying both open areas and those dominated by annual weeds .
Importance to Livestock and Wildlife
Livestock: The early green foliage of Lewis flax is sought out by livestock [61,62]. However, domestic sheep are reported to have been poisoned by grazing on Lewis flax, which has been shown to contain a cyanogenetic substance (capable of making cyanide) [1,42]. Dittberner and Olson  also list Lewis flax as a plant suspected to be poisonous to livestock.
A study done at the Desert Experimental Range of the Intermountain Forest and Range Experiment Station, Utah revealed that Lewis flax has a high preference rating as antelope forage and is generally used during the summer and fall. The preference rating was higher during wet years versus dry years because in wet years there is a greater abundance of Lewis flax available .
Other small mammals: Lewis flax is "never edible" to golden-mantled ground squirrel, and "seldom edible" to the least chipmunk in trapped and caged populations taken from a rocky, meadow habitat in the mountains of west-central Colorado .
Feeding trials with trapped deer mouse populations revealed that Lewis flax seeds were preferred, and comprised of 16.3% of their diet. The deer mice were trapped in big sagebrush-antelope bitterbrush (Artemisia tridentata-Purshia tridentata), singleleaf pinyon-Utah juniper, and Jeffrey pine-snowbrush ceanothus (Ceanothus velutinus) vegetation types in western Nevada. Preference rating (scale of 1 to 18) for Lewis flax seeds for each vegetation type were 6, 7, and 8, respectively .
Conversely, Addicott  states that the fruit of Lewis flax seems to be avoided by birds, small mammals, and insects.
|Small nongame birds||----||poor||----||fair||good|
|Upland game birds||----||poor||----||fair||poor|
Cover value: Wildlife cover values of Lewis flax for some western states are presented below .
|Small nongame birds||fair||----||fair||poor|
|Upland game birds||----||----||fair||poor|
Ethnobotanic: Cultivated flax (Linum usitatissimum) is grown both for fiber (flax) and seed oil (linseed). Linseed oil may cause skin irritation upon contact.
Ingestion causes difficulty of breathing, paralysis, and convulsions (Russell et al. 1997).
Grazing/rangeland: Blue and Lewis flax are noted to have fair forage value for livestock and wildlife during spring and winter. Plants stay green throughout the growing season providing some forage value. Birds use the seed and capsules in fall and winter. All species provide diversity to the seeded plant community.
Erosion control/reclamation/greenstripping: All flax species are noted for their value in mixes for erosion control and beautification values. The six week flowering period and showy blue flowers make seedings more aesthetically pleasing and increase plant biodiversity. Due to the semi-evergreen nature of the species, flax can also be used as a fire suppressant species in greenstrip plantings.
Wildlife: Flax is considered desirable forage for deer, antelope, and birds, either as herbage or seed. They may also provide some cover for selected small bird species.
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Linum lewisii (Linum perenne var. lewisii) (Lewis flax, blue flax or prairie flax) is a perennial plant in the family Linaceae, native to western North America from Alaska south to Baja California, and from the Pacific Coast east to the Mississippi River. It grows on ridges and dry slopes, from sea level in the north up to 3000 m altitude in the south of the species' range.
It is a slender herbaceous plant growing to 90 cm tall, with spirally arranged narrow lanceolate leaves 1–2 cm long. The flowers are pale blue or lavender to white, 1.5–3 cm diameter, with five petals.
Linum lewisii is extremely durable, even aggressive, in favorable conditions, successfully seeding even into established lawns.
- "The Plant List: A Working List of All Plant Species". Retrieved 4 October 2014.
- Jepson Flora Project: Linum lewisii
- Germplasm Resources Information Network: Linum lewisii
- USDA Plant Profile: Linum lewisii
- Mojave Desert Wildflowers, Jon Mark Stewart, 1998, pg. 141
- Illinois wildflowers: Linum perenne lewisii
- Fine gardening: Linum lewisii
|Wikimedia Commons has media related to Linum lewisii.|
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Names and Taxonomy
Comments: In Kartesz 1999's treatment of Linum, he elevates 'var. lewisii', which many place in L. perenne, to its own species.
(Pursh) Hult. [4,52,63]
Adenolinium lewisii (Pursh) LÃ¶ve
& LÃ¶ve [65,132]
Perennial blue flax (L. perenne) is a distinct, closely related species that is native to Europe [97,98]. It was once considered a synonym for L. lewisii [50,60,133].
Lewis' blue flax
western blue flax
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