Asclepias obovata |
Asclepias pumila |
|
---|---|---|
pineland milkweed |
low milkweed, plains milkweed, plains or low or dwarf milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1 (rarely more), erect to spreading, unbranched, 40–70(–200) cm, densely hirtellous to velutinous, not glaucous, rhizomes absent. |
1–12, erect, unbranched to moderately branched below, 10–30 cm, puberulent with curved trichomes, 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. |
alternate, sessile, with 1 stipular colleter on each side of leaf base; blade needlelike to narrowly linear, 2.5–5.5 × 0.05–0.1 cm, chartaceous, base cuneate, margins entire, apex acute, mucronate, venation obscure, surfaces glabrous, 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. |
extra-axillary at upper nodes, sometimes appearing terminal, pedunculate, 3–13-flowered; peduncle 0.1–2 cm, puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
6–16 mm, puberulent with curved trichomes. |
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; calyx lobes narrowly lanceolate, 2–3 mm, apex acute, puberulent with curved trichomes to glabrate; corolla pink to cream with a pink tinge, lobes reflexed with spreading tips, elliptic, 3.5–4.5 mm, apex acute, glabrous abaxially, minutely papillose at base adaxially; gynostegial column 0.8–1 mm; fused anthers green, columnar, 1–1.5 mm, wings narrowly right-triangular, closed, apical appendages deltoid; corona segments cream, sometimes tinged or striped pink, stipitate, tubular, dorsally flattened, 2–2.5 mm, exceeded by to equaling style apex, apex obtuse, glabrous, internal appendage acicular, exserted, arching towards style apex, glabrous; style apex shallowly depressed, cream. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
ovate, 5–6 × 3–5 mm, margin winged, faces smooth; coma 2–3 cm. |
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 straight pedicels, narrowly fusiform, 2.5–9.5 × 0.5–1 cm, apex acuminate to attenuate, smooth, minutely puberulent with curved trichomes to glabrate. |
Asclepias obovata |
Asclepias pumila |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering (May–)Jun–Sep; fruiting Aug–Oct. |
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. | Slopes, bluffs, plains, sandhills, dunes, rock outcrops, playas, ditches, basalt, alluvium, sandy, clay, rocky, and gravel soils, prairies, meadows, shrubby grasslands, pine woodlands. |
Elevation | 0–200 m. (0–700 ft.) | 600–2300 m. (2000–7500 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
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CO; KS; MT; ND; NE; NM; OK; SD; TX; WY
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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 linaria and A. pumila of southeastern Arizona and extreme southwestern New Mexico are the only milkweeds with densely spiraled, linear to needlelike leaves. Hybrids with A. subverticillata and A. verticillata have been documented; see discussion under these species. When not flowering, A. pumila is cryptic and easily overlooked in its grassland habitat, especially when growing among Bouteloua species. Specimens supposedly from Illinois and Arizona (C. Mohr [US]) undoubtedly have incorrect label data. A population in the Sacramento Mountains of southern New Mexico (Otero County) appears to be a significant southern disjunction. (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 | A. verticillata var. pumila | |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 321. (1817) | (A. Gray) Vail: Bull. Torrey Bot. Club 25: 175. (1898) |
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