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broom groundsel, broom senecio, broom-like ragwort, grass-leaf ragwort, many-head groundsel

tall blacktip ragwort

Habit Subshrubs, 20–120+ cm (taproots forming woody crowns). Perennials, (20–)35–70(–80+) cm (rhizomes or caudices branched, erect to weakly creeping).
Herbage

usually glabrous, sometimes sparsely, unevenly hairy.

floccose-tomentose to canescent, sometimes unevenly glabrescent.

Stems

usually multiple (branching and arching upward).

1–(2–5).

Leaves

evenly distributed (proximal often smaller);

sessile or obscurely petiolate;

blades narrowly linear to filiform (or parted into linear-filiform lobes), 5–10 cm × 1–6 mm, bases ± linear, ultimate margins entire.

progressively reduced distally; petiolate;

blades oblong-ovate to oblanceolate, (5–)10–30 × 1.5–4(–6) cm, bases tapered, margins dentate (denticles, dark, callous; mid leaves similar, sessile, smaller; distal leaves bractlike).

Ray florets

± 5 (± 13);

corolla laminae 8–12 mm.

(± 3) ± 5;

corolla laminae 5–8 mm.

Phyllaries

usually ± 8, sometimes ± 13, (5–)6–9(–10) mm, tips green or minutely black.

(± 5) ± 8, 6–8 mm, tips black.

Calyculi

0 or of 1–3+ (minute, inconspicuous) bractlets.

of 2–5 linear bractlets (lengths to 1/3 phyllaries).

Heads

10–20(–60) in compound corymbiform arrays (involucres cylindric or narrowly campanulate, 3–6 mm diam.).

20–60+ in corymbiform or subpaniculiform arrays.

Cypselae

usually hirtellous, sometimes glabrous.

glabrous.

2n

= 40.

= 40. (A report of 2n = 46 is presumably erroneous.)

Senecio spartioides

Senecio atratus

Phenology Flowering summer–fall. Flowering late spring–early fall.
Habitat Open, dry disturbed sites, especially stream banks and hillsides Dry or drying, rocky or sandy sites in coniferous areas, especially sites with frequent disturbance
Elevation 1000–3500 m (3300–11500 ft) 2800–4000 m (9200–13100 ft)
Distribution
from FNA
AZ; CA; CO; NE; NM; NV; SD; TX; UT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; NM; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Plants with the leaves parted into lobes that are seldom more than 1 mm wide have been recognized as Senecio spartioides var. multicapitatus (or as S. multicapitatus); expression of the character is inconsistent throughout the range and recognition of the two entities is all but impossible to maintain.

Senecio spartioides apparently hybridizes with S. eremophilus in Garfield County, Utah, and perhaps elsewhere (cf., Holmgren, Reveal, and LaFrance 3463, BRY, KSC, NY). The name Senecio toiyabensis rests upon materials that suggest introgression with S. fremontii. Some specimens usually referred to 41. S. pattersonensis suggest introgression with S. spartioides.

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

Source FNA vol. 20, p. 559. FNA vol. 20, p. 554.
Parent taxa Asteraceae > tribe Senecioneae > Senecio 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. flaccidus, 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. sphaerocephalus, S. spribillei, S. squalidus, S. sylvaticus, S. taraxacoides, S. triangularis, S. viscosus, S. vulgaris, S. warnockii, S. wootonii
S. actinella, S. amplectens, S. ampullaceus, S. aphanactis, S. arizonicus, S. aronicoides, S. astephanus, S. bigelovii, S. blochmaniae, S. californicus, S. cannabifolius, S. clarkianus, S. crassulus, S. elegans, S. elmeri, S. eremophilus, S. ertterae, S. erucifolius, S. flaccidus, 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
Synonyms S. andersonii, S. incurvus, S. multicapitatus, S. serra var. sanctus, S. spartioides var. granularis, S. toiyabensis S. atratus var. milleflorus, S. milleflorus
Name authority Torrey & A. Gray: Fl. N. Amer. 2: 438. (1843) Greene: Pittonia 3: 105. (1896)
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