Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Senecio wootonii

Senecio riddellii

Wooton's butterweed, Wooton's ragwort

Riddell's groundsel, Riddell's ragwort
Habit Perennials, (15–)20–45(–60) cm (caudices erect or weakly spreading). Subshrubs, 30–100 cm (taproots forming woody crowns).
Herbage

nearly always glaucous, glabrous.

glabrous.
Stems

single or clustered.

usually multiple (branching upward).
Leaves

(thickish and turgid) progressively reduced distally;

petiolate;

blades ovate or obovate to lanceolate, 4–9(–15+) × 1.5–3(–4+) cm, bases tapered, margins wavy or subentire (often with callous denticles; mid and distal leaves sessile, bractlike).

± evenly distributed (proximal often withering before flowering, pendulous);

sessile or obscurely petiolate;

blades linear-filiform (or irregularly pinnately divided into linear-filiform lobes), blades or lobes 4–9 cm × 1–5 mm, bases ± linear, ultimate margins entire.
Ray florets

8–10;

corolla laminae 4–10 mm.

± 8;

corolla laminae (often falling early) 8–10 mm.
Phyllaries

± 13 (± 21), 6–9 mm, tips green to brownish (not blackened).

± 13, 7–10(–12+) mm, tips green.
Calyculi

of 1–3+ oblong to lance-linear bractlets (less than 3 mm).

usually of 3–8+ lance-linear to filiform bractlets (lengths 1/10–1/3 phyllaries).
Heads

(3–)8–24+ in corymbiform arrays.

5–20+ in close, corymbiform arrays (involucres campanulate, 7–10 mm diam.).
Cypselae

glabrous.

hirtellous.
2n

= 40.

= 40.

Senecio wootonii

Senecio riddellii
Phenology Flowering spring–summer. Flowering mostly mid summer–fall, occasionally spring.
Habitat Damp or drying sites, often in rocky, moderately disturbed sites Sandy or rocky open sites, especially drying, open, flood plains
Elevation 2000–3500 m (6600–11500 ft) 600–2500 m (2000–8200 ft)
Distribution
from FNA
AZ; CO; NM; TX; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; KS; NE; NM; OK; SD; TX; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Senecio wootonii reaches its southern limit in Coahuila and Chihuahua, Mexico; farther south, it is replaced by S. toluccanus de Candolle, a similar, larger, more robust species.

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

Senecio riddellii intergrades morphologically with S. spartioides. Typically, the former has larger heads with campanulate involucres 7–10 mm diam.; the latter has cylindric involucres rarely more than 6 mm diam.

Senecio riddellii is poisonous to livestock. It is now locally scarce because of efforts to eradicate it.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 20, p. 554. FNA vol. 20, p. 560.
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. spartioides, S. sphaerocephalus, S. spribillei, S. squalidus, S. sylvaticus, S. taraxacoides, S. triangularis, S. viscosus, S. vulgaris, S. warnockii
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. 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. anacletus S. filifolius var. fremontii, S. riddellii var. parksii, S. spartioides var. fremontii, S. spartioides var. parksii, S. spartioides var. riddellii
Name authority Greene: Bull. Torrey Bot. Club 25: 122, plate 331, figs. 1, 2. (1898) Torrey & A. Gray: Fl. N. Amer. 2: 444. (1843)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America

The species comparison tool is brought to you by:
Northwest Wildflowers