Hibiscus coulteri |
Hibiscus denudatus |
|
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Coulter's hibiscus, desert rose-mallow |
pale face, paleface rose-mallow, rock hibiscus, rocl hibiscus |
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Habit | Subshrubs, to 2 m, herbage with appressed-stellate and simple hairs throughout. | Subshrubs, to 0.8 m, herbage densely ± yellowish stellate-tomentose throughout. |
Stems | stellate hairs of younger stems dense, appressed, 4-armed, arms approximate in pairs, aligned with stem axis, lines of fine, curved hairs absent or obscured; older growth grayish, rough, glabrescent. |
older twigs yellowish brown, glabrescent, line of fine hairs obscured by other pubescence or absent. |
Leaves | stipules linear-subulate, 3–10 mm; petiole primarily in distal 1/2, sometimes themselves shallowly pinnately lobed, surfaces scabridulous, hairs appressed-stellate, obscure nectary present abaxially on midvein near base. |
stipules narrowly triangular to subulate, 1–3 mm; petiole to 1/2 as long as blade, adaxial fine, curved hairs absent or obscured by other pubescence; blade oblong or broadly to narrowly ovate (often folded in pressed specimens), usually unlobed, rarely shallowly 3-angulate-lobate, mostly 1.2–3 × 1–2.5 cm, base cuneate to rounded or truncate, margins irregularly and coarsely dentate or dentate-crenate, apex broadly acute to truncate, surfaces stellate-tomentose, ± obscured nectary present abaxially on midvein near base. |
Inflorescences | solitary flowers in axils of distal leaves. |
solitary flowers in axils of distal leaves. |
Pedicels | jointed below apices, to 17 cm, usually much exceeding subtending leaves; involucellar bractlets 8–14, linear-subulate, 1–2 cm, margins ciliate. |
obscurely joined below apex, 0.5–2 cm, equaling or exceeding subtending petioles; involucellar bractlets 7–10, often absent, narrowly triangular to subulate, to 0.6 cm, margins not ciliate. |
Flowers | erect or ascending; calyx divided 3/4+ length, funnelform, 1.4–2.2 cm, equaling or slightly exceeding involucel, lobes narrowly lanceolate-triangular, margins ciliate, apices attenuate, nectaries absent; corolla rotate, petals yellow to cream, usually with dark to obscure maroon lines basally, asymmetrically obovate to broadly obovate, 1.6–4 × 1–3.5 cm, margins ± entire, sparingly hairy abaxially where exposed in bud; staminal column straight, yellow or cream, 0.6–1.4 cm, bearing filaments throughout, free portion of filaments not secund, 1–3 mm; pollen yellow-orange; styles cream, 1.5–5 mm; stigmas maroon or cream. |
ascending to erect; calyx divided 2/3–4/5 length, funnelform, 0.7–1.6 cm, lobes narrowly triangular-ovate, apices acuminate, nectaries absent; corolla rotate, petals pale purple or pink to nearly white, with maroon spot or lines basally, asymmetrically obovate, 1.3–3 × 0.9–2 cm, margins ± entire, finely hairy abaxially where exposed in bud; staminal column straight, pink, 0.4–1.1 cm, bearing filaments throughout, free portion of filaments not secund, 1–3 mm; pollen dark orange; styles pale pink, 1.5–4 mm; stigmas pale pink to maroon. |
Capsules | pale olivaceous gray with darker median stripe on each valve, ovoid or ellipsoid, 0.7–1.7 cm, to 2/3 calyces, apex rounded, hairy near apex or glabrous throughout. |
dull yellow-green with darker medial stripe on each valve, drying straw-colored, ovoid to subglobose, 0.6–1 cm, shorter than calyces, apex apiculate, glabrous or with minute hairs near apex and on sutures. |
Seeds | dark brown, angulately reniform-ovoid, 2.4–3 mm, silky-hairy ± throughout. |
dark brown, angulately reniform-ovoid, 2.2–3 mm, whitish, silky-hairy ± throughout, hairs 3–4 mm. |
2n | = 22 (Mexico: Durango). |
|
Hibiscus coulteri |
Hibiscus denudatus |
|
Phenology | Flowering nearly year-round. | Flowering year-round. |
Habitat | Desert, rocky slopes | Desert, often rocky |
Elevation | 600–1600 m (2000–5200 ft) | 30–1800 m (100–5900 ft) |
Distribution |
AZ; NM; TX; Mexico (Baja California, Chihuahua, Coahuila, Durango, Nuevo León, Sonora, Zacatecas)
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AZ; CA; NM; NV; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora)
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Discussion | Hibiscus coulteri has been recorded in the southern half of Arizona; in Otero County, New Mexico; and in the region west of the Pecos River in Texas. A naturally occurring hybrid between Hibiscus coulteri and H. denudatus (Hibiscus ×sabei Weckesser) has recently been documented from western Texas (W. Weckesser 2011). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Hibiscus denudatus has been recorded from Imperial, Riverside, San Bernardino, and San Diego counties in southern California; from southernmost Nevada (southern Clark County); from the southern half and near the Grand Canyon in Arizona; from southwestern New Mexico; and from the region west of the Pecos River in Texas. As noted in the previous species, a naturally occurring hybrid between Hibiscus denudatus and H. coulteri (Hibiscus ×sabei Weckesser) has recently been documented from western Texas (W. Weckesser 2011). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 6, p. 256. | FNA vol. 6, p. 257. |
Parent taxa | Malvaceae > subfam. Malvoideae > Hibiscus | Malvaceae > subfam. Malvoideae > Hibiscus |
Sibling taxa | ||
Name authority | Harvey ex A. Gray: Smithsonian Contr. Knowl. 3(5): 23. (1852) | Bentham: Bot. Voy. Sulphur, 7, plate 3. (1844) |
Web links |