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Island Koenigia - Koenigia islandica
State Rank Reason (see State Rank above)
Rare in Montana, where it is only known from several, high elevation sites on the Beartooth Plateau. Data are insufficient for accurately determining population levels and trend, though populations probably flucuate widely from year to year. The known occurrences and their habitat do not appear to be at any significant risk of adverse impacts from human activities.
Island Koenigia is a small, glabrous annual with simple or sparsely branched, ascending to nearly prostrate stems that are 1-4 cm high. The narrowly elliptic, entire-margined, opposite or alternate leaves are fleshy, reddish-tinged, and 2-5 mm long. Small plants may have only a single pair of leaves. Tiny flowers occur in small clusters on top of the stems or in the axils of the upper leaves. Each flower has 3 greenish calyx lobes and 3 stamens. Petals are lacking. The fruit is a tiny 3-angled achene.
Flowering in August.
Small, alpine species of Polygonum have 4-5 tepals. Small specimens of Epilobium alpinum may be mistaken for K. islandica, but the former has leaves with a more prominent midvein, and the flowers have a linear ovary.
Circumpolar, extending south in North America to scattered alpine summits in the Rocky Mountains as far south as Colorado.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Wet, open, gravelly soil in seepage areas in the alpine zone.
Ecological Systems Associated with this Species
Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).
- Additional ReferencesLegend: View Online Publication
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- Fertig, W. and M. Bynum. 1994. Biological report on the proposed Twin Lakes Research Natural Area. Unpublished report to the Shoshone National Forest. Wyoming Natural Diversity Database, Laramie, Wyoming. 33 pp. plus appendices.
- Lesica, P. 1993. Vegetation and flora of the Line Creek Plateau area, Carbon County, Montana. Unpublished report to USDA Forest Service, Intermountain Research Station. Montana Natural Heritage Program, Helena, Montana. 30 pp.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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