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butterweed

balsam groundsel, Canadian butterweed

Habit Annuals or biennials, 20–70+ cm; fibrous-rooted (caudices relatively short, weak). Perennials, 20–45+ cm; subrhizomatous (bases weakly branched, ascending to erect).
Stems

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

1 or 2–4, loosely clustered, glabrous or sparsely tomentose proximally.

Basal leaves

(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.

petiolate;

blades lanceolate to narrowly elliptic or oblanceolate, 30–60+ × 10–20+ mm, bases tapering, sometimes obtuse, margins subentire to dentate or serrate.

Cauline leaves

gradually reduced (weakly clasping, similar to basal).

gradually reduced (proximals petiolate, sublyrate; mids sessile, not clasping, lanceolate, dissected, incised, or lacerate; distals sessile, bractlike).

Peduncles

bracteate, glabrous or bases tomentose.

usually bracteate, sometimes ebracteate, glabrous.

Ray florets

(8–)13;

corolla laminae 7–9 mm.

0, 8, or 13;

corolla laminae (pale yellow) 5–10+ mm.

Disc florets

35–50+;

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

50–65+;

corolla tubes 2–3 mm, limbs 2–3 mm.

Phyllaries

(13–)21, green, 5–7 mm, glabrous.

13 or 21, green, 5–8+ mm, glabrous.

Calyculi

conspicuous (bractlets 2.5–4 mm).

inconspicuous.

Heads

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

2–10+ in loose or compact, corymbiform arrays.

Cypselae

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

pappi 3–4 mm.

1–2 mm, usually glabrous, sometimes hispidulous on ribs;

pappi 3.5–4.5 mm.

2n

= 46.

= 44, 46, 92.

Packera glabella

Packera paupercula

Phenology Flowering (Feb–)mid Mar–late May. Flowering May–late Jun (south), late Jun–early Aug (north).
Habitat Open wet areas, edges of woodlands, stream banks, roadsides, meadows, marshes, fallow fields Wet meadows, open woodlands, along streams, rocky outcrops
Elevation 0–600 m (0–2000 ft) 0–3000 m (0–9800 ft)
Distribution
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]
from FNA
AK; AL; CO; DC; GA; IA; ID; IL; IN; KY; MA; MD; ME; MI; MN; MT; NC; ND; NH; NJ; NY; OH; PA; SD; TN; UT; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Ecologically and morphologically, Packera paupercula is the most variable species of the genus in North America. Some “phases” have been treated as separate species, subspecies, varieties, forms, and races. Variation within P. paupercula hints at some interesting evolutionary relationships; characteristics used to separate taxa overlap. Much of the morphologic variation in this species may be due to hybridization and introgression. I do not recognize any of the infraspecific taxa that have been proposed.

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

Source FNA vol. 20, p. 588. FNA vol. 20, p. 595.
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. 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
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. 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. 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 glabellus, Senecio carolinianus, Senecio densiflorus, Senecio lobatus, Senecio lyratus, Senecio mississipianus Senecio pauperculus, Senecio balsamitae, Senecio balsamitae var. firmifolius, Senecio balsamitae var. thomsoniensis, Senecio crawfordii, Senecio flavovirens, Senecio gaspensis, Senecio multnomensis, Senecio robbinsii var. subtomentosus, Senecio tweedyi
Name authority (Poiret) C. Jeffrey: Kew Bull. 47: 101. (1992) (Michaux) Á. Löve & D. Löve: Bot. Not. 128: 520. (1976)
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