Miner's Candle - Cryptantha scoparia
State Rank Reason (see State Rank above)
This species is documented from a single area in Carbon County, where it is widely disjunct from the nearest known occurrences in southwest Wyoming and central Idaho. In 1991 about 1,000 plants were reported occupying less than one acre. The habitat is subject to grazing, and may be affected by exotic weed encroachment. Additional surveys and monitoring data are needed.
- Details on Status Ranking and Review
Score2-3 - Very Small to Small: Population size is imprecisely known but is believed to be <10,000 individuals.
Score3 - Local Endemic or Very Small Montana Range: Generally restricted to an area <10,000 sq. miles (equivalent to the combined area of Phillips and Valley Counties) or <6 Sub-basins (4th code watersheds) Range-wide OR limited to one Sub-basin in Montana
Area of Occupancy
Score3 - Very Low: Generally occurring in 3 or fewer Subwatersheds (6th Code HUC’s).
Score1 - Moderate: Species is restricted to a specific habitat that is more widely distributed or to several restricted habitats and is typically dependent upon relatively unaltered, good-quality habitat (C Values of 5-7).
ScoreNA - Rank factor not assessed.
CommentTrends are unknown. Population levels probably fluctuate greatly from year to year.
Score0-1 - Low to Medium.
CommentNo specific threats have been identified for the species or its immediate habitat.
Score1 - Moderate Vulnerability: Specific biological attributes, unusual life history characteristics or limited reproductive potential makes the species susceptible to extirpation from stochastic events or other adverse impacts to its habitat and slow to recover.
Raw Conservation Status Score
10 to 12 total points scored out of a possible 16 (Rarity factors and threats only).
Miner's Candle is a slender annual herb with simple or branched stems that are 5-15 cm high. The alternate, narrow, strap-shaped leaves are 2-4 cm long; those at the base are usually brown by the time the plant is fruiting. Stems are sparsely covered with straight hairs appressed to the surface, while the leaves have some spreading hairs. Tiny, white flowers are borne on coiled stalks that unwind and elongate as flowering progresses from the base upward. The corolla is ca. 1 mm high and has a small united portion below and 5 spreading petals above. The narrow calyx is covered with bristly hairs and becomes 4-6 mm long in fruit. The 4 lance-shaped nutlets are ca. 2 mm long, ca 0.5 mm wide, and are finely bumpy.
Flowering occurs in June, however mature nutlets are necessary for positive identification.
The many similar-appearing, small-flowered, annual members of the genus Cryptantha are best distinguished by the ornamentation of the mature nutlets. Cryptantha scoparia has narrowly lance-shaped nutlets that are less than 7 mm wide, with tiny hooked prickles. This combination of characters is diagnostic.
Snake River plains of Idaho, extending into adjacent Oregon, Nevada, and Utah. Cronquist reports disjuncts on the Salmon River in Idaho and in Yakima County, Washington. Also known from SW Wyoming and NW Colorado.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Miner's candle is known from the Pryor Mountains, where it grows at about 1370 m (4500 feet) in dry, sandy, limestone uplands dominated by Artemisia tridentata and Agropyron spicatum (Lesica and Achuff 1992). Other associates include Phlox hoodii, Arenaria hookeri, Camissonia andina, Camissonia minor, Chenopodium album, Bromus tectorum, Descurainia pinnata, Bouteloua gracilis, Gilia leptomeria, Stipa comata, and Lappula redowskii.
Ecological Systems Associated with this Species
The species is an annual, and population sizes may vary greatly from year to year (Lesica and Achuff 1992). Plants are usually found where vegetation is relatively sparse. The small size of the flowers and the regularity of fruiting suggest that C. scoparia is self-pollinated.
This species' habitat is subject to grazing, although the effects are unknown. Populations could be vulnerable to invasive weeds, which can be spread by livestock. However, livestock may also spread the seeds of C. scoparia and help create open habitat required for seedling establishment.
Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).
- Literature Cited AboveLegend: View Online Publication
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Additional ReferencesLegend: View Online Publication
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- Kisch, H.R. 2015. An inventory of carbon stocks under native vegetation and farm fields in south-central Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 67 p.
- Lesica, P. and P. F. Stickney. 1994. Noteworthy collections: Montana. Madrono 41:228-231.
- Lesica, P. and P.L. Achuff. 1992. Distribution of vascular plant species of special concern and limited distribution in the Pryor Mountain desert, Carbon County, Montana. Unpublished report to the Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 105 pp.
- Quire, R.L. 2013. The sagebrush steppe of Montana and southeastern Idaho shows evidence of high native plant diversity, stability, and resistance to the detrimental effects of nonnative plant species. M.Sc. Thesis. Bozeman, MT: Montana State University. 124 p.
- Rundquist, V.M. 1973. Avian ecology on stock ponds in two vegetational types in north-central Montana. Ph.D. Dissertation. Bozeman, MT: Montana State University. 112 p.