Overview
Distribution
Localities documented in Tropicos sources
United States (North America)
Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.
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Anonymous. 1986. List-Based Rec., Soil Conserv. Serv., U.S.D.A. Database of the U.S.D.A., Beltsville.
http://www.tropicos.org/Reference/1103
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National Distribution
United States
Origin: Native
Regularity: Regularly occurring
Currently: Present
Confidence: Confident
Type of Residency: Year-round
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National Distribution
United States
Origin: Native
Regularity: Regularly occurring
Currently: Present
Confidence: Confident
Type of Residency: Year-round
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Physical Description
Diagnostic Description
Leaves 3-12 mm wide, lower surface pilose to villous, at least on midvein and at basal margin, base cuneate to rounded; petioles (1-)1.5-4 mm long. Oahu, Molokai, Maui, and Kauai. (Wagner et al., 1990)
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Ecology
Habitat
Comments: Open or closed Prosopis forest on bare, corraline soils (Oahu). Open, mixed shrubs on lithified dunes or raised reef (Molokai).
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Comments: A variety of dry shrubland communities, including Naio (Myoporum) Coastal Dry Shrubland, open mixed shrubland assemblages on lithified dunes or raised reef, and dry shrublands on broad ridgetops, gently sloped lands, gulch slopes, talus slopes, or cliffs. Also occurs in Prosopis forests with open or closed canopies on bare, corraline soils. Coastal and inland areas, apparently restricted to calcareous substrates. 5-200 m.
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Population Biology
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 6 - 20
Comments: 9 CURRENT AND 5 HISTORICAL OCCURRENCES.
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Conservation
Conservation Status
National NatureServe Conservation Status
United States
Rounded National Status Rank: N2 - Imperiled
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NatureServe Conservation Status
Rounded Global Status Rank: T2 - Imperiled
Reasons: Endemic to the Ewa Plains at the southwestern tip of Oahu, and the northwestern coast of Molokai. There are 7 current occurrences. All of the Oahu occurrences are threatened by habitat destruction and modification stemming from the urbanization of the Ewa Plains. The Molokai occurrences are threatened by deer, cattle, and off-road vehicles. All the occurrences are threatened by alien plant competition and fire.
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National NatureServe Conservation Status
United States
Rounded National Status Rank: N2 - Imperiled
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Threats
Comments: Habitat destruction & modification for development, competition with aggressive weedy plants, insect infestations.
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Management
Biological Research Needs: Reasons for low reproduction, effects of insect infestations effects from parasitic vine.
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Wikipedia
Euphorbia skottsbergii
Euphorbia skottsbergii (syn. Chamaesyce skottsbergii)[1] is a rare species of flowering plant in the euphorb family known by the common names coastal sandmat and Skottsberg's broomspurge. It is endemic to Hawaii, where it is found in coastal shrublands[2] on Oʻahu, Molokaʻi, Maui, and Kahoʻolawe.[3] Like other Hawaiian euphorbs, this plant is known locally as ʻakoko.
The taxonomy of this plant is still being studied; the name and number of varieties have changed over the years and are still in flux. In 1982 the rare variety kalaeloana was added to the endangered species list of the United States.[4] This plant was and still is known only from Oʻahu's ʻEwa Plains between Kalaeloa (Barber's Point) and Pearl Harbor. It had been reduced in population by a number of factors, including Navy activity, pollution, destruction by bulldozer on private property, quarrying, agriculture, fire, development and construction of housing, roads, an oil refinery, and resort property, and expansion of the harbor.[3][4] The plant's human-caused decline probably started with the arrival of the Polynesians.[3] Other threats include non-native plant species, especially kaunaoa pehu (Cassytha filiformis), kiawe (Prosopis pallida), Chinese violet (Asystasia gangetica), and buffel grass (Cenchrus ciliaris).[3] Potentially damaging insects that visit the plant include croton moth (Aechaea janata) and spiraling whitefly (Aleurodicus dispersus).[3]
Genetic analyses has led to recent changes in taxonomy. The rare var. kalaeloana is now called var. skottsbergii.[3] The populations of the plant that grow on Molokai are genetically more different from var. skottsbergii than from the more common var. vaccinioides, and have been named var. audens.[3][5] Furthermore, the endangered variety on Oʻahu is different enough that it should probably be named a new species.[3]
References
- ^ GRIN Species Profile
- ^ "Chamaesyce skottsbergii". Native Plants Hawaii. http://nativeplants.hawaii.edu/plant/view/Chamaesyce_skottsbergii. Retrieved 2011-02-21.
- ^ a b c d e f g h USFWS. Chamaesyce skottsbergii var. kalaeloana. August 2, 2007.
- ^ a b USFWS. Determination that Euphorbia skottsbergii var. kataeloana (ʻEwa Plains ʻAkoko) is an endangered species. Federal Register August 24, 1982.
- ^ Morden, C. W. and M. Gregoritza. (2005). Population variation and phylogeny in the endangered Chamaesyce skottsbergii (Euphorbiaceae) based on RAPD and ITS analyses. Conservation Genetics 6:6 969-79.
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Names and Taxonomy
Taxonomy
Comments: USFWS tracks as synonym 01 - Chamaesyce skottsbergii var. KALAELOANA (8/93). GENUS COSMOPOLITAN, 14 SPECIES ENDEMIC TO HAWAIIAN ISLANDS. ORIGINALLY DESCRIBED AS A Euphorbia. KOUTNIK IN WAGNER ET AL. RECOGNIZES THIS TAXON AS Chamaesyce. VAR. KALAELOANA & VAR. AUDENS HAVE BEEN LUMPED WITH THIS ONE. According to Derral Herbst, USFWS (Honolulu) endangered status for var. kalaeloana is upheld for var. skottsbergii.
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