Chaenactis stevioides Hook. & Arn.

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.

Plants 5–30(–45) cm; proximal indument grayish, ± arachnoid-sericeous (tardily glabrescent except around nodes). Stems 1–12 (sometimes decumbent); branches proximal and/or distal. Leaves 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. Heads (± radiant) mostly 3–20+ per stem. Peduncles 1–5(–10) cm, usually stipitate-glandular distally and, often, ± arachnoid. Involucres ± hemispheric to obconic (bases green, rounded in fruit). Phyllaries: longest 5.5–8(–10) mm; outer stipitate-glandular and/or ± arachnoid in fruit, apices erect, blunt, ± rigid. Florets: corollas white to pinkish, cream, or pale yellow, 4.5–6.5 mm (inner); peripheral corollas spreading, zygomorphic, enlarged. Cypselae (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). 2n = 10.

Chaenactis furcata Stockwell; C. gillespiei Stockwell; C. latifolia Stockwell; C. mexicana Stockwell; C. stevioides var. brachypappa (A. Gray) H. M. Hall; C. stevioides var. thornberi Stockwell

Chaenactis stevioides H. & A. Bot. Beech. Voy. 353. 1838
Chaenactis florihunda Greene, Pittonia 3: 168. 1897.
A freely branched annual; stem 1-2 dm., seldom 3 dm. high, floccose when young, glabrate in age, glandular-puberulent above; leaves 5-8 cm. long, once or twice pinnatifid into linear spreading divisions; peduncles 1-5 cm. long, glandular-puberulent; involucre 8-9 mm. high, 10-15 mm. broad; bracts linear, obtusish, with faint midrib, glandular-puberulent; corollas white, 5 mm. long, those of the marginal flowers only moderately enlarged but irregularly 5toothed; achenes 5 mm. long, hirsute; squamellae of the central flowers oblong-lanceolate, two-thirds to three-fourths as long as the corolla, those of the marginal flowers shorter, unequal, some often very small.
Type locality: Snake County, Idaho.
Distribution: Wyoming to Idaho, southern California, Sonora, and New Mexico.

Chaenactis brachypappa A. Gray, Proc. Am. Acad. 8: 390
1872.
Chaenactis stevioides brachypappa H. M. Hall, Univ. Calif. Publ. Bot. 3: 194. 1907.
A branched annual; stem 1-2 dm. high, floccose when young; branches ascending;
leaves 3-5 cm. long, bipinnatifid with oblong or linear, divaricate obtuse divisions, floccose
when young; peduncles 1-5 cm. long; involucre 7-8 mm. high, 10-12 mm. broad; bracts
broadly linear, glandular-puberulent, obtuse; corollas dull-white, about 4 mm. long, those
of the marginal flowers with scarcely dilated limb obliquely 5-toothed; achenes nearly 5 mm.
long, hirsutulous; squamellae 4, all short, obtuse. [Seems to grade into C. stevioides.]
Type locality: Pahranagat Mountains, Nevada. Distribution: Southern Nevada and southern California.

Chaenactis furcata is a Mexican species of flowering plants in the aster family. It grows on the Baja California Peninsula in northwestern Mexico, the State of Baja California (sometimes erroneously called Baja California Norte).

Chaenactis stevioides est une plante de la famille des Asteraceae, originaire du sud-ouest des États-Unis et du nord du Mexique.

Chaenactis stevioides là một loài thực vật có hoa trong họ Cúc. Loài này được Hook. & Arn. mô tả khoa học đầu tiên năm 1839.