Pygmy Goldenweed - Tonestus pygmaeus
State Rank Reason (see State Rank above)
Known in Montana from 1 historical collection from Lolo Peak. Other historical locations previously reported for MT have all been based on mis-identified specimens of Tonestus lyallii
Pygmy Goldenweed is a mat-forming perennial with several stems that are 1-6 cm high and which arise from a taproot and branched rootcrown. The narrowly oblong, entire-margined basal leaves are 1-5 cm long and 1-5 mm wide. The alternate stem leaves are only somewhat smaller. Foliage is glabrous, except for sticky hairs toward the top. The bell-shaped flower heads are solitary on the stem tips and 8-10 mm high. Each head has ca. 2 series of slightly overlapping narrow involucral bracts. Tips of the outer heads are blunt, but those of the inner heads are pointed. The 10-35 yellow rays are 6-8 mm long, and the yellow disk flowers are 5-7 mm long. The elongate achenes are topped by numerous, white to tan bristles, forming a pappus.
Flowering in August.
Tonesetus lyallii has sticky, glandular foliage. Other species formerly placed in Haplopappus with solitary flower heads have very reduced stem leaves. Erigeron linearis has yellow rays, but its leaves are linear.
Southeastern Wyoming to northern New Mexico, with a disjunct population in the Bitterroot Mountains of southwestern Montana.
Alpine slopes and meadows.
Ecological Systems Associated with this Species
- Commonly Associated with these Ecological Systems
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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- Hall, H.M. 1928. The genus Haplopappus, a phylogenetic study in the compositae. Carnegie Institution of Washington Publication No. 389, Washington D.C. 391 pp.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.