Hymenoxys richardsonii

(Hooker) Cockerell

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

Common names: Richardson’s bitterweed pingue rubberweed
Endemic
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.

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, glanddotted (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.

Distribution

V21-1102-distribution-map.gif

Alta., Sask., Ariz., Colo., Mont., N.Dak., N.Mex., Tex., Utah, Wyo.

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
... more about "Hymenoxys richardsonii"
not tailed +, rounded +  and obtuse +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
indeterminate +  and determinate +
Mark W. Bierner +
(Hooker) Cockerell +
decurrent +
Picradenia richardsonii +
hairy +  and glabrous +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Richardson’s bitterweed +  and pingue rubberweed +
0.7 cm7 mm <br />0.007 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
hairy +  and glabrous +
obpyramidal +
fertile +  and bisexual +
fertile +  and bisexual +
Alta. +, Sask. +, Ariz. +, Colo. +, Mont. +, N.Dak. +, N.Mex. +, Tex. +, Utah +  and Wyo. +
hairy +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
discoid +  and radiate +
in paniculiform to corymbiform arrays +  and singly +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
0.6 cm6 mm <br />0.006 m <br /> (3.2 cm32 mm <br />0.032 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
campanulate +
0.7 cm7 mm <br />0.007 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
deltate +
dentate to pinnatifid or palmatifid +  and entire +
obovate +  and ovate +
unequal +  and subequal +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
2-carpellate +
persistent +
4 +  and 8 +
obovate +  and lanceolate +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
28 +  and 50 +
Bull. Torrey Bot. Club +
bearing subulate enations +, hairy +  and bristly +
pitted +  and smooth +
conic;ovoid;conic;ovoid;hemispheric +
2 +  and 11 +
aristate +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
exalbuminous +
subequal;unequal +
purple-red-tinted +  and green +
1 +  and 20 +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Dugaldia +  and Plummera +
Hymenoxys richardsonii +
Hymenoxys +
species +
urceolate +  and campanulate +
dilated +
toothed +  and entire +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
shrub +  and subshrub +