Asclepias curtissii |
Asclepias scaposa |
|
---|---|---|
Curtiss' milkweed |
bear mountain milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1, erect, often purplish, sometimes branched in inflorescence, 15–100 cm, puberulent with curved trichomes, not glaucous, rhizomes absent. |
1–5+, erect, unbranched (rarely at base), 15–20 cm, pilosulous, not glaucous, rhizomes absent. |
Leaves | opposite, petiolate, with 1 or 2 stipular colleters on each side of petiole; petiole 4–7 mm, puberulent with curved trichomes; blade oblong, elliptic, or oval to obovate, oblanceolate, ovate, or lanceolate, 1.8–5 × 0.5–2.5 cm, chartaceous, base obtuse to cuneate or rounded, margins entire, apex truncate to emarginate or acute, mucronate, venation brochidodromous to eucamptodromous, surfaces sparsely puberulent on midvein with curved trichomes, margins inconspicuously ciliate to glabrate, 2–6 laminar colleters. |
opposite, sessile or petiolate, with 1 stipular colleter on each side of petiole; petiole 0–6 mm, pilosulous to glabrate; blade oval to elliptic, 6–8 × 1.5–2.5 cm, membranous, base cuneate, margins crisped, apex obtuse to acute, venation eucamptodromous, surfaces sparsely hirtellous, margins ciliate, laminar colleters absent. |
Inflorescences | terminal and extra-axillary at upper nodes, sessile or pedunculate, 15–45-flowered; peduncle 0–4 cm, puberulent on 1 side with curved trichomes, with 1 caducous bract at the base of each pedicel. |
terminal, solitary, pedunculate, 15–30-flowered; peduncle 7–17 cm, pilose, bracts absent or few. |
Pedicels | 10–14 mm, sparsely puberulent with curved trichomes. |
15–20 mm, pilose. |
Flowers | erect; calyx lobes lanceolate, 2–3 mm, apex acute, glabrous; corolla green with bronze or purplish tinge, lobes reflexed with spreading tips, elliptic, 4–5 mm, apex acute, glabrous; gynostegial column 0.5–1 mm; fused anthers green, obconic, 1–1.5 mm, wings broadly triangular, widest at middle, closed, apical appendages ovate; corona segments white with a green and/or purple dorsal midline, sessile, conduplicate and dorsally flattened, 5–6 mm, greatly exceeding style apex, apex attenuate, glabrous, internal appendage falcate, exserted, sharply inflexed over style apex, glabrous; style apex shallowly depressed, green to cream. |
erect to pendent; calyx lobes narrowly lanceolate, 2–2.5 mm, apex acute, pilose; corolla green with purplish tinge (reddish purple), lobes reflexed, elliptic, 4–5 mm, apex acute, glabrous; gynostegial column 0.5–1 mm; fused anthers brown, cylindric, 1.5–2 mm, wings curved, wider at base, apical appendages ovate; corona segments cream, sometimes yellow- or red-tinged or yellow or red at base, sessile, tubular, 2–3 mm, exceeding style apex, base saccate, apex truncate, dentate, glabrous, internal appendage falcate, exserted, arching above style apex, glabrous; style apex shallowly depressed, green or cream. |
Seeds | ovate, 8–9 × 5–6 mm, margin winged, erose, faces sparsely papillose; coma 3.5–4 cm. |
not seen. |
Follicles | erect on upcurved pedicels, fusiform, 8–10.5 × 0.8–1.5 cm, apex long-acuminate, smooth, puberulent with curved trichomes. |
erect on upcurved pedicels, fusiform, 5–6 × 1–1.5 cm, apex long-acuminate, smooth, pilosulous. |
Asclepias curtissii |
Asclepias scaposa |
|
Phenology | Flowering Apr–Oct; fruiting Jul–Oct. | Flowering Mar–Aug; fruiting May. |
Habitat | Low ridges, sandy soils, oak-palmetto sand scrub, pinelands. | Ridges, slopes, limestone, rocky, silty, and clay soils, pine-oak woodlands, desert scrub, thorn scrub. |
Elevation | 0–50 m. (0–200 ft.) | 600–2000 m. (2000–6600 ft.) |
Distribution |
FL
|
TX; Mexico (Coahuila, Nuevo León, San Luis Potosí, Zacatecas) |
Discussion | Asclepias curtissii is endemic to white-sand substrates at interior and coastal sites on the Florida peninsula. Although the species is not considered to face imminent threat of extirpation, the scrub habitats in which it is found have been, and continue to be, heavily impacted by development. Asclepias curtissii cannot be mistaken for any other milkweed in its range when in flower; however, it occurs in the same habitats as A. tomentosa, and these species overlap considerably in vegetative features. The leaves of A. curtissii can be distinguished from those of A. tomentosa by trichomes limited to the midvein (versus sparsely to densely puberulent or tomentulose throughout). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The long-pedunculate, terminal inflorescence combined with short stature is distinctive in Asclepias scaposa. Although the locality of one of the syntypes was attributed to New Mexico by E. L. Greene, that is the only report for that state. Both syntypes were collected by Charles Wright for the United States-Mexico boundary survey, but neither of his labels indicates that they were collected in New Mexico. It is very likely that both collections were made in Texas or northeastern Mexico, and New Mexico is excluded from the distribution here. The common name Bear Mountain milkweed may refer to a ridge in the northwestern portion of the Davis Mountains, although no collections are known from this area. The few collections and observations that have been made in Texas are from scattered locations in Brewster, Crockett, Pecos, Presidio, Reeves, and Terrell counties, and conservation status in the United States merits assessment. In Mexico, A. scaposa also has been rarely collected, except for a local area in Nuevo León (Municipio de Galeana). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 14. | FNA vol. 14. |
Parent taxa | Apocynaceae > Asclepias | Apocynaceae > Asclepias |
Sibling taxa | ||
Synonyms | Oxypteryx curtissii | |
Name authority | A. Gray: Proc. Amer. Acad. Arts 19: 85. (1883) | Vail: Bull. Torrey Bot. Club 25: 171. (1898) |
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