Chaenactis thompsonii
Chaenactis glabriuscula
Thompson's pincushion
common yellow chaenactis, yellow pincushion
mostly 5–15+, ascending to erect.
mostly 1–5(–12; sometimes ± horizontal);
branches proximal and, often, distal.
mostly cauline, 2–5 cm;
largest blades ± elliptic, ± plane, 1-pinnately lobed;
lobes mostly 2–5 pairs, remote, ± plane.
basal (often withering) and cauline, 1–10 cm;
largest blades linear or ± elliptic, plane to 3-dimensional, succulent or not, (0–)1–2-pinnately lobed;
primary lobes 1–7 pairs, remote to ± congested, ultimate lobes ± plane, involute, twisted, and/or terete.
ascending to erect, 2–5 cm.
1–20(–30) cm, distally stipitate-glandular, ± villous, arachnoid-sericeous, lanuginose, and/or glabrescent.
± obconic.
± hemispheric to obconic or broadly cylindric.
corollas bright to dark yellow, 4–8 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 4.5–10 mm;
outer stipitate-glandular, ± villous, arachnoid-sericeous, lanuginose, and/or glabrescent in fruit, apices erect, blunt, ± rigid.
mostly 1–3 per stem.
(± radiant) mostly 1–20+ per stem.
7–9 mm (eglandular);
pappi: longest scales 3.5–5 mm.
3–9 mm (± terete);
pappi of (1–)4 scales in 1 series, or of (5–)8 scales in 2, abruptly unequal series, longest scales (1–)2–8 mm.
= 12.
Chaenactis thompsonii
Chaenactis glabriuscula
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.)
Varieties 5 (5 in the flora).
The diverse and intergrading forms here included in Chaenactis glabriuscula have been divided by P. Stockwell (1940) and subsequent workers into as many as four species and ten varieties. Chaenactis glabriuscula is known from the southern two-thirds of the Californian Floristic Province and adjacent desert edges. It has been reported in Massachusetts as a garden escape (variety unspecified); it is not expected to persist there outside cultivation.
Complete interfertility among the taxa recognized here as Chaenactis glabriuscula vars. glabriuscula, megacephala, and lanosa was demonstrated by P. Stockwell (1940). Intraspecific crosses involving C. glabriuscula var. orcuttiana were much less successful; C. glabriuscula var. heterocarpha was not tested. As noted by W. J. Hooker and G. A. W. Arnott ([1830–]1841) and D. W. Kyhos (1965), some forms of C. glabriuscula differ from C. stevioides or C. fremontii only in corolla color, which can be lost in older or poorly preserved specimens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Pappi of (5–)8 scales in 2, abruptly unequal series | var. heterocarpha |
1. Pappi of (1–)4(–5) scales in 1 series | → 2 |
2. Proximal indument whitish, ± densely lanuginose; leaves ± basal (persistent) | var. lanosa |
2. Proximal indument grayish, ± arachnoid, or glabrescent; leaves basal (withering) and cauline | → 3 |
3. Largest leaf blades succulent, mostly 2-pinnately lobed; stems ± horizontal | var. orcuttiana |
3. Largest leaf blades scarcely succulent, 1(–2)-pinnately lobed; stems ascending to erect | → 4 |
4. Longest phyllaries 7–9 × 2–3 mm, outer glabrescent in fruit; pappi: lengths of longest scales ± 0.9(–1) times corollas | var. megacephala |
4. Longest phyllaries 5–7 × 1–2 mm, outer (at least medially) ± arachnoid-sericeous and, often, ± stipitate-glandular in fruit; pappi: lengths of longest scales 0.4–0.7 times corollas | var. glabriuscula |
WA
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
CA
