Woolly-head Clover - Trifolium eriocephalum
State Rank Reason (see State Rank above)
Known from eight large occurrences on the Bitterroot National Forest. Invasive weeds, particularly spotted knapweed, are a problem in the habitat occupied by the species. Timber harvest and related road-building activities may also negatively impact populations. However, Trifolium eriocephalum appears capable of tolerating some level of disturbance.
Woolly-head Clover is a perennial with erect stems that are 20-60 cm tall and arising from a thick taproot and a branched rootcrown. The leaves have three leaflets that are 2-7 cm long and elliptic to oblong with sharply toothed margins. The base of each leaf petiole is enlarged to form two lance-shaped wings, or stipules, that are 2-5 cm long. The foliage is sparsely to densely long-hairy. 25-80 flowers are borne in globose clusters at the ends of the main stem or on side branches. The pinkish to red flowers are nodding and 12-17 mm long with a hood-shaped upper petal, or banner, as well as two narrow, separate petals on the side (wings); the two lower petals are united into a boat-shaped petal, or keel. The calyx has five long teeth at the mouth and is covered with long, feather-like hairs. The fruit is a small pod with 4 ovules.
Ours is subspecies arcuatum McDermott. There are many species of clover in Montana, and a technical key should be consulted for positive identification. This species can be distinguished from other perennial species of Trifolium occurring at lower elevations by the combination of having an erect, leafy habit, lacking a leafy involucre below the inflorescence, and by its long feathery hairs on the calyx teeth.
WA to MT south to CA, NV and UT (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Dry meadows, woods and margins in the foothill and lower montane zones.
Ecological Systems Associated with this Species
- Additional ReferencesLegend: View Online Publication
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- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.