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Douglas' dustymaiden, dusty pincushions, dusty-maidens, false yarrow, hoary false yarrow

Habit Biennials or perennials, (3–)8–50(–60) cm (sometimes slightly woody or flowering first year, not or scarcely cespitose, not matted).
Stems

usually 1–5(–12).

Leaves

basal (sometimes withering) and ± cauline, 1.5–12(–15) cm, indument ± persistent.

Phyllaries

longest 9–15(–17) mm;

outer ± stipitate-glandular and, often, arachnoid to lanuginose and, sometimes, sparsely villous.

Heads

(1–)2–25+ per stem.

2n

= 12, 24, 36 (plus dysploid numbers and triploids).

Chaenactis douglasii var. douglasii

Phenology Flowering May–Sep.
Habitat Open sandy, gravelly, or rocky substrates in shrublands, woodlands, forests, often unstable or recently disturbed sites
Elevation 400–3500 m (1300–11500 ft)
Distribution
from FNA
AZ; CA; CO; ID; MT; ND; NM; NV; OR; SD; UT; WA; WY; AB; BC
[BONAP county map]
Discussion

Variety douglasii is known in and east of the Sierra Nevada and Cascade Ranges, to the western edge of the northern Great Plains, and in the Klamath Ranges and North Coast Ranges of northwestern California (where its lowest elevations occur). It is known from most mountains within that range; northward it also descends to the higher plains and valley floors. A report of var. douglasii from Saskatchewan was not verified by me. Seeds of var. douglasii are commercially available and are planted for revegetation or horticultural purposes and it may be found outside its native range.

Four ploidy levels were documented across the range of var. douglasii by J. S. Mooring (1965, 1980) and P. H. Raven and D. W. Kyhos (1961). Mooring’s (1980) data suggested that diploids are more frequent at higher elevations in major mountain chains and are more often mixed with polyploids at lower elevations or in areas of Pleistocene or later disturbance. The chromosome numbers listed above are predominant; Mooring (1965, 1980, 1992) also documented 2n = 14, 15, 26, or 30 as regular bivalents. Additional numbers, involving various combinations of bivalents with univalents, tetravalents, and/or extra chromosomes, have been observed.

Most of the diploid elements of var. douglasii are distinctive and are connected by a morphologically continuous series of polyploids (usually assigned to var. achilleifolia). Some diploid forms (including var. rubricaulis and Chaenactis ramosa) appear repeatedly and discontinuously in suitable habitats. In particular, forms named var. montana seem to arise wherever the species reaches sufficient elevation. Such populations have no historic or genetic cohesion to justify their recognition as a collective taxon, even though their reduced stature may become genetically fixed in each instance. (Variety alpina, recognized below with hesitation, may be just an extreme such case.) Chaenactis angustifolia of the northern Rocky Mountains and possibly C. pedicularia of Colorado are more distinctive morphologically and geographically, and merit further study and possible varietal status.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 21.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Chaenactidinae > Chaenactis > sect. Macrocarphus > Chaenactis douglasii
Sibling taxa
C. douglasii var. alpina
Synonyms C. angustifolia, C. douglasii var. achilleifolia, C. douglasii var. glandulosa, C. douglasii var. montana, C. douglasii var. rubricaulis, C. pedicularia, C. pumila, C. ramosa
Name authority unknown
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