Difference between revisions of "Hymenoxys richardsonii"

(Hooker) Cockerell

Bull. Torrey Bot. Club 31: 468. 1904.

Common names: Richardson’s bitterweed pingue rubberweed
Basionym: Picradenia richardsonii Hooker Fl. Bor.-Amer. 1: 317, plate 108. 1833 (as richardsoni)
Treatment appears in FNA Volume 21. Treatment on page 440. Mentioned on page 435, 436.
FNA>Volume Importer
FNA>Volume Importer
(No difference)

Revision as of 18:46, 24 September 2019

Perennials, 7–34 cm (polycarpic; usually with highly branched woody caudices). Stems 1–20(–30+), usually green throughout, rarely purple-red-tinted proximally, branched distally, glabrous or ± hairy. Leaves: blades simple or lobed (lobes 3–7), glabrous or ± hairy, gland-dotted (basal leaf bases densely long-villous-woolly); mid leaves lobed (lobes 3–5, terminal lobes 0.7–2 mm wide). Heads 5–300+ per plant, in corymbiform arrays. Peduncles 1–5 cm, ± hairy. Involucres campanulate, 7–11 × 7–14 mm. Phyllaries in 2 series, unequal; outer 8–13, obovate to ovate to lanceolate, basally connate 1/2 their lengths, 3.5–8 mm, apices acuminate to acute; inner 8–18, obovate, 3–8 mm, apices mucronate. Ray florets 7–14; corollas yellow, 7–17 × 3–6 mm. Disc florets 25–75+; corollas 3–5 mm. Cypselae narrowly obpyramidal, 2–3 mm; pappi of 4–8 obovate to lanceolate, aristate scales 1.8–3.5 mm. 2n = 30.

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Key

1 Stems 1–10; leaves ± hairy; heads 5–35+ per plant; involucres 8–11 × 9–14 mm; outer phyllaries 9–13, weakly to moderately keeled; ray corollas 11–17 mm Hymenoxys richardsonii var. richardsonii
1 Stems (2–)5–20(–30+); leaves glabrous or sparsely hairy; heads (30–)80–250(–300+) per plant; involucres 7–8 × 7–9 mm; outer phyllaries 8–9, strongly keeled; ray corollas 7–11 mm Hymenoxys richardsonii var. floribunda