Asclepias obovata |
Asclepias lanuginosa |
|
---|---|---|
pineland milkweed |
asclépiade laineuse, side-cluster milkweed, small-green milkweed, woolly milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1 (rarely more), erect to spreading, unbranched, 40–70(–200) cm, densely hirtellous to velutinous, not glaucous, rhizomes absent. |
1 or 2 (rarely more), erect to spreading, unbranched, 7–20 cm, densely hirtellous to pilose, not glaucous, rhizomatous. |
Leaves | opposite, petiolate, with 1 or 2 stipular colleters on each side of petiole; petiole 1–4 mm, densely hirtellous to velutinous; blade oblong or elliptic to obovate or ovate, 4–9 × 1–3.5 cm, subcoriaceous, base rounded or truncate to cordate, margins sometimes crisped, apex acute to truncate, sometimes emarginate, often mucronate, venation brochidodromous, surfaces densely hirtellous to velutinous abaxially, hirtellous adaxially, margins ciliate, 8–12 laminar colleters. |
opposite or alternate, petiolate, with 1 stipular colleter on each side of petiole; petiole 1–2 mm, hirtellous; blade oblong or lanceolate to narrowly lanceolate, 4–8 × 0.5–2.7 cm, chartaceous, base cuneate to rounded or subcordate, margins entire, apex acute to obtuse, venation eucamptodromous to reticulodromous, surfaces hirtellous, margins ciliate, laminar colleters absent. |
Inflorescences | extra-axillary, sometimes also appearing terminal, sessile or pedunculate, 7–31-flowered; peduncle 0–0.5 cm, densely hirtellous to velutinous, with 1 caducous bract at the base of each pedicel. |
terminal, usually solitary, pedunculate, 17–50-flowered (rarely more); peduncle 1–3 cm, densely hirtellous to pilose, with 1 caducous bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
9–13 mm, hirtellous to pilose. |
Flowers | erect to pendent; calyx lobes elliptic, 5–6 mm, apex acute, densely hirtellous; corolla green, sometimes tinged reddish or bronze, lobes reflexed, sometimes with spreading tips, elliptic, 7–9 mm, apex acute, glabrous abaxially, minutely papillose at base adaxially; gynostegial column 1–1.5 mm; fused anthers green, obconic, 2.5–4 mm, wings right-triangular, open at base, apical appendages broadly ovate; corona segments bronze to yellow, often tinged red, sometimes apically cream or pale, stipitate, tubular, somewhat flattened laterally, flared at base, 5–8 mm, greatly exceeding style apex, apex rounded, flared, glabrous, internal appendage falcate, exserted, sharply incurved over style apex, glabrous; style apex shallowly depressed, green. |
erect to spreading; calyx lobes narrowly lanceolate, 1.5–2 mm, apex acute, hirtellous; corolla greenish cream, sometimes purple-tinged, lobes reflexed, oblong, 3–5 mm, apex acute, glabrous; gynostegial column 0–0.2 mm; fused anthers green, broadly cylindric, 1.5–2 mm, wings triangular, widest below middle, closed, apical appendages ovate; corona segments cream to greenish cream, sessile, chute-shaped, margins incurved, appressed to column, 2–3.5 mm, exceeded by style apex, base saccate, apex rounded, glabrous, internal appendage absent or obscure, glabrous; style apex shallowly depressed, green to greenish cream. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
ovate, 6–7 × 4–5 mm, faces minutely rugulose; comose. |
Follicles | erect on upcurved pedicels, narrowly to broadly fusiform, 7.5–12.5 × 1.5–2.5 cm, apex acuminate, smooth, densely hirtellous to velutinous. |
erect on upcurved pedicels, fusiform, 8–10 × 0.8–1.5 cm, apex long-acuminate, smooth, hirtellous to pilose. |
2n | = 22. |
|
Asclepias obovata |
Asclepias lanuginosa |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering May–Aug; fruiting Jul–Aug. |
Habitat | Hills, slopes, flats, ridges, sandhills, ditches, seeps, bogs, sandstone, sandy, rocky, silty, and clay soils, pine flatwoods, pine savannas, pine, pine-oak, and bottomland hardwood forests, prairies, often following fires. | Sandhills, dunes, moraines, bluffs, slopes, sandstone, limestone, sandy, gravel, or rocky soils, prairies, pine barrens and forests, oak savannas. |
Elevation | 0–200 m. (0–700 ft.) | 200–700 m. (700–2300 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
|
IA; IL; KS; MN; ND; NE; SD; WI; MB
|
Discussion | Asclepias obovata is a common milkweed of seasonally wet, sandy soils in pine woodlands of the Gulf Coastal Plain and (rarely) the southern Atlantic Coastal Plain. It is rare and considered to be of conservation concern in Arkansas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Asclepias lanuginosa is highly cryptic due to its small stature and early flowering. It resembles a short, hirtellous form of A. viridiflora. In addition to the differences in vestiture, A. lanuginosa can be distinguished from that species by the terminal inflorescence and the cream-colored corona segments. Due to severe habitat loss in the tallgrass prairie region, A. lanuginosa has apparently declined and is of conservation concern over much of its range, that is, in Illinois, Iowa, Kansas, North Dakota, South Dakota, and Wisconsin. It is more secure in Nebraska, but an overall re-assessment of the status of this species is warranted. The only report from Montana is from the “Yellowstone expedition,” which may not have been collected in the state. R. E. Woodson Jr. (1954) considered A. lanuginosa Kunth (a later homonym) to be the correct name for a Mexican species, A. otarioides E. Fournier. He soon realized that A. lanuginosa Nuttall has priority, but prior usage and his extensive annotations produced lingering confusion over the correct name of the Mexican species. Torrey’s replacement name for this species, A. nuttalliana, is illegitimate, as it was superfluous on publication. (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 | ||
Name authority | Elliott: Sketch Bot. S. Carolina 1: 321. (1817) | Nuttall: Gen. N. Amer. Pl. 1: 168. (1818) |
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