Asclepias obovata |
Asclepias perennis |
|
---|---|---|
pineland milkweed |
aquatic milkweed, aquatic or white swamp or swamp or thin-leaf milkweed |
|
Habit | Herbs. | Subshrubs or herbs, cespitose. |
Stems | 1 (rarely more), erect to spreading, unbranched, 40–70(–200) cm, densely hirtellous to velutinous, not glaucous, rhizomes absent. |
1–5, erect, sparsely to moderately branched, especially towards base, 30–60 cm, puberulent with curved trichomes in a line to glabrate, 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. |
persistent or gradually caducous from the base, opposite, petiolate, with 1 or 2 stipular colleters on each side of petiole on a ciliate interpetiolar ridge; petiole 10–12 mm, ciliate; blade narrowly elliptic to oval or oblong, 5–14 × 0.3–3 cm, membranous or chartaceous, base cuneate, margins entire, apex acute to attenuate or acuminate, minutely mucronate, venation faintly brochidodromous to eucamptodromous, surfaces sparsely puberulent with curved trichomes, more densely on veins, to glabrate, margins inconspicuously 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, 12–30-flowered; peduncle 1.5–5 cm, puberulent with curved trichomes, sometimes only on 1 side, with 1 caducous bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
7–13 mm, puberulent with curved trichomes, sometimes only on 1 side. |
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 to linear, 1.2–1.5 mm, apex acute, puberulent with curved trichomes; corolla white to pink-tinged, lobes reflexed with spreading tips, elliptic, 3–4 mm, apex acute to obtuse, glabrous abaxially, minutely papillose at base adaxially; gynostegial column 0.8–1.2 mm; fused anthers brown, cylindric, 1.5–2 mm, wings narrowly right-triangular, closed, apical appendages deltoid; corona segments white, sometimes faintly pink-tinged, stipitate, tubular, dorsally rounded, 1.5–2.5 mm, slightly exceeding style apex, apex obtuse to acute, glabrous, internal appendage acicular, exserted, arching over style apex, glabrous; style apex shallowly depressed, white, sometimes pink-tinged. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
broadly oval, 12–15 × 11–14 mm, margin broadly winged, faces smooth; coma absent. |
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. |
pendulous on declined pedicels, lance-ovoid, 4–7 × 1–2.5 cm, apex long-acuminate, smooth, glabrous. |
Asclepias obovata |
Asclepias perennis |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering (Mar–)Apr–Nov; fruiting Jun–Dec. |
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. | Swamps, streamsides, ditches, bottomlands, flood plains, marshes, saturated or inundated clay, silty, and sandy soils, pine-oak, oak, and mixed hardwood forests, riparian woods, pine flatwoods. |
Elevation | 0–200 m. (0–700 ft.) | 0–300(–500?) m. (0–1000(–1600?) ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
|
AL; AR; FL; GA; IL; IN; KY; LA; MO; MS; SC; TN; TX
|
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 perennis is the most hydrophytic North American milkweed and is often found emerging from standing water in swamps and ditches. The pendulous fruits and hairless seeds are distinctive; it is the only milkweed in the United States with seeds lacking a coma, and only one of three such species in North America. It is widely distributed along the coastal plain; inland (Arkansas, Illinois, Indiana, Kentucky, Missouri, Tennessee), it is restricted to the valleys of the Mississippi and Ohio rivers and their tributaries. (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) | Walter: Fl. Carol., 107. (1788) |
Web links |