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Douglas' groundsel, Mono groundsel, shrubby butterweed, shrubby ragwort, threadleaf groundsel, threadleaf ragwort

Habit Subshrubs or shrubs, (30–)40–120+ cm (taproots forming woody crowns).
Herbage

glabrous or ± lanate-tomentose.

Stems

usually multiple (little branched, arching-erect).

Leaves

± evenly distributed;

sessile or obscurely petiolate;

blades narrowly linear to filiform (or pinnatifid, the segments linear to filiform), 3–10(–12) cm, bases ± linear, ultimate margins entire or remotely toothed (fascicles of smaller leaves sometimes borne in axils of larger leaves).

Ray florets

usually ± 8 or ± 13, sometimes ± 21;

corolla laminae 10–15(–20) mm (mostly yellow, sometimes ochroleucous).

Phyllaries

± 13 or ± 21+, 5–10(–12) mm, tips green or minutely black.

Calyculi

usually of 3–5+ bractlets (lengths often to 1/2+ phyllaries), sometimes 0.

Heads

(1–)3–10(–20+) in corymbiform or subcorymbiform clusters, often gathered in larger, showy arrays (involucres campanulate or cylindric).

Cypselae

hairy.

2n

= 40.

Senecio flaccidus

Distribution
from FNA
AZ; CA; CO; KS; NM; NV; OK; TX; UT; Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

The varieties of Senecio flaccidus are distinguished by morphologic tendencies and geography. The species occurs southward to central Mexico; a sound understanding of the infraspecific taxonomy must await revisionary studies that include the Mexican plants.

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

Key
1. Herbage usually tomentose (hairs whitish), sometimes unevenly glabrescent; bractlets of calyculi minute or 0; involucres cylindric or ± campanulate; phyllaries ± 13 or ± 21, 5–8+ mm
var. flaccidus
1. Herbage ± tomentose, glabrate, or glabrous; bractlets of calyculi well developed (lengths mostly 1/3 – 1/2 phyllaries); involucres ± campanulate; phyllaries ± 21, 7–12 mm
→ 2
2. Plants usually ± tomentose (usually with persistent, uneven grayish tomentum), sometimes unevenly glabrescent; California w of crests of Sierra Nevada and related ranges
var. douglasii
2. Plants glabrate or glabrous; California deserts e of crest of Sierra Nevada and eastward
var. monoensis
Source FNA vol. 20, p. 558.
Parent taxa Asteraceae > tribe Senecioneae > Senecio
Sibling taxa
S. actinella, S. amplectens, S. ampullaceus, S. aphanactis, S. arizonicus, S. aronicoides, S. astephanus, S. atratus, S. bigelovii, S. blochmaniae, S. californicus, S. cannabifolius, S. clarkianus, S. crassulus, S. elegans, S. elmeri, S. eremophilus, S. ertterae, S. erucifolius, S. fremontii, S. hydrophiloides, S. hydrophilus, S. integerrimus, S. jacobaea, S. lemmonii, S. lugens, S. lyonii, S. megacephalus, S. mohavensis, S. multidentatus, S. neowebsteri, S. parryi, S. pattersonensis, S. pseudoarnica, S. pudicus, S. quaylei, S. rapifolius, S. riddellii, S. sacramentanus, S. scorzonella, S. serra, S. sheldonensis, S. soldanella, S. spartioides, S. sphaerocephalus, S. spribillei, S. squalidus, S. sylvaticus, S. taraxacoides, S. triangularis, S. viscosus, S. vulgaris, S. warnockii, S. wootonii
Subordinate taxa
S. flaccidus var. douglasii, S. flaccidus var. flaccidus, S. flaccidus var. monoensis
Name authority Lessing: Linnaea 5: 161. (1830)
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