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gray feverfew, Gray's feverfew

American feverfew, wild feverfew, wild quinine

Habit Biennials (sometimes flowering first year or persisting), 10–30(–60+) cm. Perennials, 30–60(–100+) cm.
Leaf

blades ovate or rounded-deltate to elliptic, 30–80(–120+) × 10–20(–40+) mm, usually ± pinnately or sub-bipinnately lobed, ultimate margins entire, faces strigillose, usually also with erect hairs 1–2 mm and gland-dotted.

blades ovate to lanceolate, 30–350+ × 20–120+ mm, margins usually crenate to serrate, sometimes coarsely toothed or somewhat lobed (then mostly toward bases), faces hispid to hirtellous or ± scabrous, gland-dotted.

Peduncles

2–8(–12+) mm.

1–8(–12+) mm.

Pistillate florets

5;

corolla laminae 0 or ± coroniform, 0.1–0.5 mm.

5(–6);

corolla laminae ovate to oblong or orbiculate, 1–2+ mm.

Disc florets

20–30+.

15–35+.

Phyllaries

outer 5 lance-ovate to elliptic, 2.5–3+ mm, inner 5 ± orbiculate, 3–3.5 mm.

outer 5(–6) lanceolate to broadly ovate, 3–5 mm, inner 5(–6) ± orbiculate, 4–6 mm.

Heads

disciform or obscurely radiate, borne in open, ± paniculiform arrays.

radiate, borne in corymbiform to paniculiform arrays.

Cypselae

± obovoid, 2–3 mm; pappus-like enations 2, ± erect, deltate to ovate, 0.5–1 mm (sometimes a third, subulate spur near apex adaxially).

± obovoid, 3–4+ mm; pappus-like enations 0 or 2(–4), erect to spreading, ± subulate or threadlike, fragile, 0.3–0.6+ mm.

2n

= 36, 68, 72.

= 72.

Parthenium confertum

Parthenium integrifolium

Phenology Flowering Mar–Oct. Flowering May–Sep.
Habitat Sandy plains, openings in mesquite grasslands Glades and barrens, prairies, disturbed sites
Elevation 20–2000 m (100–6600 ft) 10–500 m (0–1600 ft)
Distribution
from FNA
AZ; NM; TX; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CT; GA; IA; IL; IN; KS; KY; LA; MA; MI; MN; MO; MS; NC; NY; OH; OK; PA; SC; TN; TX; VA; WI; WV
[WildflowerSearch map]
[BONAP county map]
Discussion

As evidenced by the synonymy, Parthenium integrifolium as here circumscribed has been variously partitioned by other taxonomists. For the present, I see no justification for segregating species from, or for formal recognition of infraspecific taxa within P. integrifolium.

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

Source FNA vol. 21, p. 22. FNA vol. 21, p. 22.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Parthenium Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Parthenium
Sibling taxa
P. alpinum, P. argentatum, P. hysterophorus, P. incanum, P. integrifolium, P. ligulatum
P. alpinum, P. argentatum, P. confertum, P. hysterophorus, P. incanum, P. ligulatum
Synonyms P. confertum var. divaricatum, P. confertum var. lyratum, P. confertum var. microcephalum P. auriculatum, P. hispidum, P. hispidum var. auriculatum, P. integrifolium var. auriculatum, P. integrifolium var. henryanum, P. integrifolium var. hispidum, P. integrifolium var. mabryanum, P. radfordii
Name authority A. Gray: Proc. Amer. Acad. Arts 17: 216. (1882) Linnaeus: Sp. Pl. 2: 988. (1753)
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