Search Field Guide
Advanced Search
MT Gov Logo
Montana Field Guide

Montana Field Guides

Island Koenigia - Koenigia islandica

Species of Concern

Global Rank: G4
State Rank: S2
* (see State Rank Reason below)

Agency Status
MNPS Threat Rank: 3
C-value: 10

External Links

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.
General Description
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.

Diagnostic Characteristics
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.

Species Range

Range Comments
Circumpolar, extending south in North America to scattered alpine summits in the Rocky Mountains as far south as Colorado.

Summary of Observations Submitted for Montana
Number of Observations: 13

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Wet, open, gravelly soil in seepage areas in the alpine zone.

Ecological Systems Associated with this Species

Login Logout
Citation for data on this website:
Island Koenigia — Koenigia islandica.  Montana Field Guide.  .  Retrieved on , from