Chaenactis artemisiifolia
Chaenactis sect. Acarphaea
artemisia leaf chaenactis, white pincushion
usually 1, erect;
branches mainly distal.
basal (withering) and cauline, 3–15(–20) cm;
largest blades ± plane, not succulent;
primary lobes mostly 5–10 pairs, ultimate lobes ± crowded, antrorse, lanceolate to elliptic, plane.
largest blades deltate to ± ovate [broadly elliptic], (2–)3–4-pinnately lobed, not gland-dotted.
1.5–6 cm.
ascending to erect.
± hemispheric, mostly 10–15 mm diam.
paleae 0.
corollas white to pinkish, actinomorphic, ± equal.
5–7 mm.
longest 7–10(–12) mm, ± densely villous, not or sparsely glandular;
apices (all) erect, ± green, acute or scarcely acuminate, not aristate, ± plane.
outer acute to acuminate-aristate.
discoid (mostly 3–20+ per stem).
compressed, 4–7 mm;
pappi 0 or coroniform (of ± 10 scales, longest 0.1–0.5 mm).
± terete or compressed;
pappi 0, coroniform (of ± 10 scales), or of 4(–5) [10–16] scales in 1 [2–3] series.
= 8.
= 16.
Chaenactis artemisiifolia
Chaenactis sect. Acarphaea
In the flora area, Chaenactis artemisiifolia is known from the Transverse and Peninsular ranges and seaward valleys of southwestern California. It is fire-adapted; its germination is significantly enhanced by exposure to biomass smoke (J. E. Keeley and C. J. Fotheringham 1998).
Chaenactis lacera Greene, the eighteenth species of the genus, is known from coastal portions (including islands) of the western Vizcaíno Desert in Baja California and Baja California Sur, Mexico. Forms of C. artemisiifolia sometimes resemble C. lacera in coastal southern California (P. Stockwell 1940), where C. lacera could eventually be introduced. Besides the key characteristics above, C. lacera differs from C. artemisiifolia by its largest leaf blades broadly ± elliptic, 2–3-pinnately lobed, ultimate lobes remote, recurved to retrorse, ± linear, involute (leaf blades appearing ± skeletal).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 3 (2 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Phyllaries: apices (all or inner) usually reddish, acuminate, aristate, terete; receptacles: paleae (0–)3–10+ (± phyllary-like, apices visible among mature floret buds); leaves: ultimate lobes ± terete; cypselae ± terete; involucres mostly 5–10 mm diam | C. carphoclinia |
1. Phyllaries: apices (all) ± green, acute or scarcely acuminate, not aristate, ± plane; receptacles: paleae 0; leaves: ultimate lobes plane or involute; cypselae compressed; involucres mostly 10–25 mm diam | → 2 |
2. Pappi 0 or coroniform (of ± 10 scales, longest 0.1–0.5 mm); involucres mostly 10–15 mm diam.; phyllaries ± densely villous, not or sparsely glandular | C. artemisiifolia |
2. Pappi of 10–16 scales in 2–3 subequal series, longest scales 4–6 mm; involucres mostly 20–25 mm diam.; phyllaries ± glandular, not or sparsely villous | C. lacera (see 1 Chaenactis artemisiifolia) |
CA
WildflowerSearch
iNaturalist
USDA Plants Database
