Parthenium confertum
Parthenium alpinum
gray feverfew, Gray's feverfew
alpine feverfew, Arkansas River feverfew
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 oblanceolate to spatulate, 6–18(–35) × 1–3(–4+) mm, margins entire, faces strigilloso-sericeous (gray) and obscurely gland-dotted.
2–8(–12+) mm.
0–5(–30) mm.
5;
corolla laminae 0 or ± coroniform, 0.1–0.5 mm.
5–8;
corolla laminae 0 (tubes ± compressed, obscurely 2–4-lobed).
20–30+.
18–28+.
outer 5 lance-ovate to elliptic, 2.5–3+ mm, inner 5 ± orbiculate, 3–3.5 mm.
outer 5–8 ± linear, 4 mm, inner 5–8 ± orbiculate, 4–5 mm.
disciform or obscurely radiate, borne in open, ± paniculiform arrays.
± disciform, borne singly.
± obovoid, 2–3 mm; pappus-like enations 2, ± erect, deltate to ovate, 0.5–1 mm (sometimes a third, subulate spur near apex adaxially).
oblanceoloid, 4 mm (narrowly winged); pappus-like enations 2, erect to spreading, ± subulate, 0.5–1 mm (a third, ± subulate element sometimes at apex of adaxial face).
= 36, 68, 72.
= 36.
Parthenium confertum
Parthenium alpinum
Parthenium alpinum is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
WildflowerSearch
iNaturalist
USDA Plants Database
