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serpentine groundsel, Siskiyou butterweed, western ragwort

butterweed

Habit Perennials, 7–15+ cm; fibrous-rooted (caudices relatively slender). Annuals or biennials, 20–70+ cm; fibrous-rooted (caudices relatively short, weak).
Stems

1, glabrous or sparsely tomentose.

1 (striated, frequently hollow, often pink- to purple-tinged), glabrous or leaf axils sparsely tomentose.

Basal leaves

(and proximal cauline) petiolate;

blades ovate, oblanceolate, or spatulate, 10–30 × 5–20 mm, bases tapering, sometimes obtuse, margins entire, subentire, or dentate.

(and proximal cauline) obscurely petiolate;

blades obovate to oblanceolate, sometimes lyrate (lateral lobes to 5 pairs, terminal lobes larger than laterals), 50–150+ × 10–30+ mm, bases tapering, ultimate margins crenate to irregularly undulate.

Cauline leaves

abruptly reduced (sessile, clasping; bractlike, entire).

gradually reduced (weakly clasping, similar to basal).

Peduncles

bracteate (bractlets red-tinged), densely lanate-tomentose.

bracteate, glabrous or bases tomentose.

Ray florets

(8–)13;

corolla laminae 6–10+ mm.

(8–)13;

corolla laminae 7–9 mm.

Disc florets

35–50+;

corolla tubes 2.5–3.5 mm, limbs 3–4 mm.

35–50+;

corolla tubes 2.5–3.5 mm, limbs 2–3 mm.

Phyllaries

(13–)21, green (tips red or dark red), densely tomentose proximally.

(13–)21, green, 5–7 mm, glabrous.

Calyculi

conspicuous (bractlets narrow, red-tinged).

conspicuous (bractlets 2.5–4 mm).

Heads

1–4+ in corymbiform arrays.

8–30+ in umbelliform or cymiform arrays (robust plants with multiple arrays).

Cypselae

1.5–2 mm, glabrous;

pappi 5–6 mm.

1–1.5 mm, sparsely hirtellous on ribs or glabrous;

pappi 3–4 mm.

2n

= 46.

= 46.

Packera hesperia

Packera glabella

Phenology Flowering mid Apr–mid Jun. Flowering (Feb–)mid Mar–late May.
Habitat Serpentine derived soils, open woodland scrub Open wet areas, edges of woodlands, stream banks, roadsides, meadows, marshes, fallow fields
Elevation 500–2500 m (1600–8200 ft) 0–600 m (0–2000 ft)
Distribution
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; FL; GA; IL; IN; KS; KY; LA; MO; MS; NC; NE; OH; OK; SC; TN; TX
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Packera hesperia is known only from the Siskiyou Mountains.

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

Packera glabella is common and almost weedy in wet, partially shaded places. The hollow, striated stems of P. glabella are distinctive.

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

Source FNA vol. 20, p. 589. FNA vol. 20, p. 588.
Parent taxa Asteraceae > tribe Senecioneae > Packera Asteraceae > tribe Senecioneae > Packera
Sibling taxa
P. anonyma, P. antennariifolia, P. aurea, P. bernardina, P. bolanderi, P. breweri, P. cana, P. cardamine, P. castoreus, P. clevelandii, P. contermina, P. crocata, P. cymbalaria, P. cynthioides, P. debilis, P. dimorphophylla, P. eurycephala, P. fendleri, P. flettii, P. franciscana, P. ganderi, P. glabella, P. greenei, P. hartiana, P. hyperborealis, P. indecora, P. ionophylla, P. layneae, P. macounii, P. malmstenii, P. millefolium, P. millelobata, P. multilobata, P. musiniensis, P. neomexicana, P. obovata, P. ogotorukensis, P. pauciflora, P. paupercula, P. plattensis, P. porteri, P. pseudaurea, P. quercetorum, P. sanguisorboides, P. schweinitziana, P. spellenbergii, P. streptanthifolia, P. subnuda, P. tampicana, P. texensis, P. tomentosa, P. tridenticulata, P. werneriifolia
P. anonyma, P. antennariifolia, P. aurea, P. bernardina, P. bolanderi, P. breweri, P. cana, P. cardamine, P. castoreus, P. clevelandii, P. contermina, P. crocata, P. cymbalaria, P. cynthioides, P. debilis, P. dimorphophylla, P. eurycephala, P. fendleri, P. flettii, P. franciscana, P. ganderi, P. greenei, P. hartiana, P. hesperia, P. hyperborealis, P. indecora, P. ionophylla, P. layneae, P. macounii, P. malmstenii, P. millefolium, P. millelobata, P. multilobata, P. musiniensis, P. neomexicana, P. obovata, P. ogotorukensis, P. pauciflora, P. paupercula, P. plattensis, P. porteri, P. pseudaurea, P. quercetorum, P. sanguisorboides, P. schweinitziana, P. spellenbergii, P. streptanthifolia, P. subnuda, P. tampicana, P. texensis, P. tomentosa, P. tridenticulata, P. werneriifolia
Synonyms Senecio hesperius, Senecio auleticus Senecio glabellus, Senecio carolinianus, Senecio densiflorus, Senecio lobatus, Senecio lyratus, Senecio mississipianus
Name authority (Greene) W. A. Weber & Á. Löve: Phytologia 49: 47. (1981) (Poiret) C. Jeffrey: Kew Bull. 47: 101. (1992)
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