Senecio squalidus
Senecio flaccidus
oxford ragwort
Douglas' groundsel, Mono groundsel, shrubby butterweed, shrubby ragwort, threadleaf groundsel, threadleaf ragwort
sparsely, unevenly floccose to subglabrous, glabrescent.
glabrous or ± lanate-tomentose.
single (branching distally).
usually multiple (little branched, arching-erect).
evenly distributed;
petiolate (proximal, petioles ± winged);
blades obovate to oblong, 4–10 × 2–4+ cm, mostly lyrate-pinnatifid to pinnate, bases tapered, ultimate margins dentate (distal leaves similar, smaller, sessile).
± 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).
± 13;
corolla laminae 5–8 mm.
usually ± 8 or ± 13, sometimes ± 21;
corolla laminae 10–15(–20) mm (mostly yellow, sometimes ochroleucous).
(± 13) ± 21, 5–6+ mm, tips black.
± 13 or ± 21+, 5–10(–12) mm, tips green or minutely black.
of 4–10+ bractlets (1–2+ mm).
usually of 3–5+ bractlets (lengths often to 1/2+ phyllaries), sometimes 0.
(3–)6–20 in open, cymiform arrays.
(1–)3–10(–20+) in corymbiform or subcorymbiform clusters, often gathered in larger, showy arrays (involucres campanulate or cylindric).
usually hairy.
hairy.
= 20.
= 40.
Senecio squalidus
Senecio flaccidus
Senecio squalidus is native in Europe, where it is a common weed. It is apparently established in the San Francisco Bay area, California and has been reported from British Columbia, New Brunswick, and Nova Scotia. It is to be expected elsewhere.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
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 |
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