Chaenactis thompsonii
Chaenactis stevioides
Thompson's pincushion
broad-flower chaenactis, desert or Esteve or broad-flower pincushion, desert pincushion, Esteve pincushion, Esteve's pincushion, Steve's dustymaiden
mostly 5–15+, ascending to erect.
1–12 (sometimes decumbent);
branches proximal and/or distal.
mostly cauline, 2–5 cm;
largest blades ± elliptic, ± plane, 1-pinnately lobed;
lobes mostly 2–5 pairs, remote, ± plane.
basal (usually withering) and ± cauline, 1–8(–10) cm;
largest blades ± elliptic, ± 3-dimensional, usually not succulent, mostly 1–2-pinnately lobed;
primary lobes 4–8 pairs, remote or ± congested, ultimate lobes ± involute and/or twisted.
ascending to erect, 2–5 cm.
1–5(–10) cm, usually stipitate-glandular distally and, often, ± arachnoid.
± obconic.
± hemispheric to obconic (bases green, rounded in fruit).
corollas white to pinkish, cream, or pale yellow, 4.5–6.5 mm (inner);
peripheral corollas spreading, zygomorphic, enlarged.
7–9 mm.
longest (10–)12–15 mm;
outer closely lanuginose, not stipitate-glandular, apices erect, ± rigid.
longest 5.5–8(–10) mm;
outer stipitate-glandular and/or ± arachnoid in fruit, apices erect, blunt, ± rigid.
mostly 1–3 per stem.
(± radiant) mostly 3–20+ per stem.
7–9 mm (eglandular);
pappi: longest scales 3.5–5 mm.
(3–)4–6.5 mm;
pappi of (1–)4(–5) scales, usually in 1 series, rarely with partial outer, abruptly unequal series, longest scales 1.5–6 mm, lengths mostly 0.3–0.9 times corollas (apices hidden among corollas at flowering).
= 10.
Chaenactis thompsonii
Chaenactis stevioides
Of conservation concern.
Chaenactis thompsonii appears to be sister to C. evermannii; it is known from the mountains of central and northwestern Washington. The similar habits of C. thompsonii and C. ramosa (= C. douglasii var. douglasii) appear to result from convergent evolution in the distinctive habitat of their type localities (Wenatchee Mountains), not from a close genetic relationship as suggested by Cronquist.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Chaenactis stevioides is found throughout the southwestern deserts; it is among the most abundant spring wildflowers in the higher Mojave Desert and southern Great Basin. It also extends seaward into west-central California. It has been reported in New York as a garden escape; it is not expected to persist there outside cultivation.
Chaenactis stevioides varies in more or less concentric zones. Plants from the core zone (centered on the Great Basin and Mojave Desert) typically have pappi and phyllaries relatively short and phyllaries predominantly stipitate-glandular (var. brachypappa). Surrounding this zone to the southwest, southeast, and northeast are plants with pappi and phyllaries relatively long and phyllaries evidently or predominantly lanuginose (var. stevioides). Scattered on the periphery in central Arizona, Baja California, and west-central and southwestern California (where hybrids may be involved; see sectional discussion) are mesophytic forms with relatively long and/or broad leaf divisions, corollas varying from white to pale yellow, and pappi and phyllaries like those of var. brachypappa (var. thornberi, C. gillespiei). An unnamed form with leaves arachnoid but otherwise like C. fremontii occurs around sand dunes in the Mojave Desert. Chaenactis furcata and C. latifolia are forms possibly influenced by C. fremontii genes, unusual substrates, or pathogens. Traits of all the above taxa are inconsistent within populations, and/or recurrent or recombinant elsewhere in the range of C. stevioides.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
WA
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
CA
OR
SW CO Wildflowers
