Asclepias brachystephana |
Asclepias connivens |
|
---|---|---|
bract milkweed, short-crowned milkweed, shortcrown milkweed |
large-flower milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 4–25, erect, unbranched or branched near base, 20–40 cm, tomentulose, not glaucous, rhizomes absent. |
1, erect, unbranched (rarely branched), 25–90 cm, minutely puberulent with curved trichomes or pilose to glabrate, 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 or petiolate, with 1 or 2 stipular colleters on each side of petiole; petiole 0–1 mm, puberulent with curved trichomes to glabrate; blade narrowly elliptic to linear or oblanceolate, 2.5–8 × 0.3–2.5 cm, chartaceous, base cuneate, margins entire, apex acute to rounded, mucronate, venation brochidodromous, surfaces sparsely pilose to glabrate, midvein puberulent with curved trichomes to glabrate, margins ciliate, 0–6 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, sometimes branched, and extra-axillary at upper nodes, pedunculate, 4–8-flowered; peduncle 0.9–6 cm, densely puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel. |
Pedicels | 9–15 mm, tomentose. |
10–20 mm, densely 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. |
spreading to pendent; calyx lobes lanceolate, 4–6 mm, apex acute, sparsely pilosulous; corollas green, sometimes tinged brown at apex, lobes reflexed with spreading tips, elliptic, 10–13 mm, apex acute to obtuse, sometimes emarginate, glabrous; gynostegial column 1–1.5 mm; fused anthers green, obconic, 3–3.5 mm, wings narrowly right-triangular, distended at base, closed, apical appendages oval; corona segments cream to pale green, stipitate, clavate, incurved, 8–10 mm, greatly exceeding style apex, apex rounded, glabrous, internal appendage a hidden crest, glabrous, apices of the 5 segments sometimes connivent; style apex depressed, green. |
Seeds | oval to ovate, 6–7 × 4–6 mm, margin winged, faces papillate-tomentulose with dendritic scales; coma 2–2.5 cm. |
ovate, 7–9 × 5–6 mm, margin winged, faces minutely and sparsely rugulose; coma 3–3.5 cm. |
Follicles | erect on upcurved pedicels, lance-ovoid, 5–7 × 1.2–1.8 cm, apex acuminate, shallowly ribbed, conspicuously striate, tomentulose. |
erect on upcurved pedicels, fusiform, 11.5–15 × 0.5–1.4 cm, apex long-attenuate, smooth, minutely pilosulous. |
Asclepias brachystephana |
Asclepias connivens |
|
Phenology | Flowering Apr–Sep(–Oct); fruiting (May–)Jun–Oct. | Flowering May–Aug(–Sep); fruiting Jul–Sep(–Nov). |
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, sandy soils, pine flatwoods and barrens, often recently burned, wet meadows, marshes, bogs, swamps. |
Elevation | 900–1900 m. (3000–6200 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
AZ; NM; TX; Mexico (Aguascalientes, Chihuahua, Coahuila, Durango, Nuevo León, Sonora, Zacatecas)
|
AL; FL; GA; 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 connivens is a singular species—the large, incurved, clavate corona segments are unlike any others in the genus. With wide leaves and large flowers, A. connivens is more conspicuous than most co-occurring milkweeds, such as A. cinerea, A. feayi, A. pedicellata, and A. viridula. It prefers wet soils and often occurs at the same sites as A. viridula and the red-orange-flowered A. lanceolata. Asclepias connivens barely enters South Carolina in Jasper and Beaufort counties and is considered rare and to be of conservation concern in that state. It has been reported from Mississippi, but there are no specimens from that state, and occurrence there seems unlikely, as A. connivens has not been documented from southwestern Alabama either. It would be interesting to discover what pollinates the large and unusual flower of A. connivens; however, there appear to be no reports of flower visitors to this species. (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 | Anantherix connivens | |
Name authority | Engelmann ex Torrey in W. H. Emory: Rep. U.S. Mex. Bound. 2(1): 163. (1859) | Baldwin in Elliott: Sketch Bot. S. Carolina 1: 320. (1817) |
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