Asclepias brachystephana |
Asclepias pedicellata |
|
---|---|---|
bract milkweed, short-crowned milkweed, shortcrown milkweed |
savanna milkweed, savannah milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 4–25, erect, unbranched or branched near base, 20–40 cm, tomentulose, not glaucous, rhizomes absent. |
1, erect, unbranched, 10–45 cm, puberulent with curved trichomes, not glaucous, rhizomes absent. |
Leaves | opposite to subopposite, petiolate, with 1 or 2 stipular colleters on each side of petiole; petiole 2–8 mm, tomentulose; blade linear-lanceolate, 5–15 × 0.3–1.3 cm, chartaceous, base cuneate to rounded, margins often obscurely crisped, apex acute, mucronate, venation brochidodromous, surfaces tomentulose to glabrate, midvein puberulent with curved trichomes, margins minutely ciliate, laminar colleters absent. |
opposite, sessile, with 1 stipular colleter on each side of leaf base; blade linear to narrowly elliptic or narrowly lanceolate, 1.5–6 × 0.1–0.8 cm, chartaceous, base cuneate, margins entire, apex acute, mucronate, venation obscure to eucamptodromous, surfaces puberulent with curved trichomes or scabridulous to glabrate, margins ciliate, 2 laminar colleters. |
Inflorescences | extra-axillary, pedunculate, 4–15-flowered; peduncle 0.2–1.5 cm, tomentose, with 1 caducous bract at the base of each pedicel. |
terminal and extra-axillary at upper nodes, pedunculate, 2–7-flowered; peduncle 0.15–1 cm, densely puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel. |
Pedicels | 9–15 mm, tomentose. |
5–13 mm, minutely puberulent with curved trichomes. |
Flowers | erect; calyx lobes ovate-lanceolate, 2–3 mm, apex acute, tomentulose; corolla red-violet, sometimes green with red tinge, lobes reflexed, ovate, 4–6 mm, apex acute, minutely pilosulous; gynostegium subsessile; fused anthers brown, cylindric, 2–2.5 mm, wings right-triangular, closed, apical appendages ovate; corona segments red-violet to pink basally, white apically, sessile, tubular, 1.5–2 mm, greatly exceeded by style apex, apex truncate, oblique, with a proximal tooth on each side, glabrous, internal appendage lingulate, slightly exserted, sharply inflexed towards gynostegium, glabrous; style apex shallowly depressed, red-violet. |
erect; calyx lobes elliptic, 2–3 mm, apex acute, sparsely puberulent with curved trichomes to glabrate; corolla yellowish green to green, lobes erect, mostly concealing corona, narrowly elliptic, 7–10 mm, apex acute, glabrous; gynostegial column 4–6 mm; fused anthers green, broadly conic, 1–1.5 mm, wings right-triangular with decurrent base, closed, apical appendages ovate; corona segments yellowish green to green, sometimes dark green at apex, sessile, conduplicate, 1.5–2.5 mm, greatly exceeded by style apex, apex incurved, rounded, glabrous, internal appendage absent; style apex flat, green. |
Seeds | oval to ovate, 6–7 × 4–6 mm, margin winged, faces papillate-tomentulose with dendritic scales; coma 2–2.5 cm. |
ovate, 5–6 × 3–4 mm, margin winged, faces sparsely and minutely rugulose; coma 2–2.5 cm. |
Follicles | erect on upcurved pedicels, lance-ovoid, 5–7 × 1.2–1.8 cm, apex acuminate, shallowly ribbed, conspicuously striate, tomentulose. |
erect on straight pedicels, fusiform, 8–14 × 0.3–0.5 cm, apex long-attenuate, smooth, densely puberulent with curved trichomes. |
Asclepias brachystephana |
Asclepias pedicellata |
|
Phenology | Flowering Apr–Sep(–Oct); fruiting (May–)Jun–Oct. | Flowering Mar–Nov(–Dec); fruiting May–Oct. |
Habitat | Plains, bajadas, pastures, arroyos, stream banks, riparian areas, limestone, igneous substrates, alluvium, gravel, clay, silty, and sandy soils, desert grasslands, desert scrub, oak-juniper, juniper, and mesquite woodlands. | Flats, streamsides, sandhills, sandy soils, pine flatwoods, savannas, pine-palmetto and oak-palmetto scrubs, often following fires. |
Elevation | 900–1900 m. (3000–6200 ft.) | 0–100 m. (0–300 ft.) |
Distribution |
AZ; NM; TX; Mexico (Aguascalientes, Chihuahua, Coahuila, Durango, Nuevo León, Sonora, Zacatecas)
|
FL; GA; NC; SC
|
Discussion | Asclepias brachystephana is a blue-gray, bushy herb with ascending foliage, few-flowered umbels of small, red and white flowers, and conspicuously striped follicles. It is unlike any other milkweed. Nonetheless, herbarium specimens are commonly confused with those of A. asperula because the herbage of A. brachystephana turns green on drying, and the leaves of A. asperula subsp. asperula are often of similar size and shape. However, leaf arrangement in A. asperula is alternate rather than opposite. The flowers of A. brachystephana are remarkably similar to, and convergent with, those of A. cutleri, A. eastwoodiana, A. ruthiae, A. sanjuanensis, and A. uncialis (M. Fishbein et al. 2011). In Arizona, A. brachystephana is restricted to the portion of the southeastern corner of the state with Chihuahuan floristic affinities, in Cochise, Graham, Pima, and Santa Cruz counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Asclepias pedicellata is found in drier habitats than some co-distributed milkweeds, such as A. connivens and A. viridula. It sometimes occurs in the same sites as A. cinerea, A. curtissii, and A. feayi. The erect petals and elongate gynostegial column are unique among Asclepias species in the flora area. The green flowers with hidden coronas and low stature of the plants can make them frustratingly cryptic in their grass-dominated habitats. Asclepias pedicellata is common only in Florida and North Carolina and is considered rare and of conservation concern in the intervening region in Georgia and South Carolina. (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 | Podostigma pedicellatum | |
Name authority | Engelmann ex Torrey in W. H. Emory: Rep. U.S. Mex. Bound. 2(1): 163. (1859) | Walter: Fl. Carol., 106. (1788) |
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