Asclepias obovata |
Asclepias viridis |
|
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pineland milkweed |
green antelopehorn, green antelopehorn or green or spider milkweed, green milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1 (rarely more), erect to spreading, unbranched, 40–70(–200) cm, densely hirtellous to velutinous, not glaucous, rhizomes absent. |
1–25, decumbent to erect, unbranched or rarely branched, 15–70 cm, inconspicuously puberulent with curved trichomes to glabrate, not glaucous, rhizomes absent. |
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 to subopposite, petiolate, with 1–4 stipular colleters on each side of petiole plus 2–4 in axil; petiole 2–6 mm, puberulent with curved trichomes to glabrate; blade oblong or ovate to oval, elliptic, or lanceolate, 3–13 × 1–6 cm, chartaceous, base rounded to subcordate, margins entire, apex obtuse to rounded, often emarginate, sometimes mucronate, venation eucamptodromous to faintly brochidodromous, surfaces puberulent with curved trichomes to glabrate, more densely so on veins, margins ciliate, 6–12 laminar colleters. |
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, pedunculate, 4–23-flowered; peduncle usually branched, 0.5–6 cm, pilosulous to puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
(8–)14–23 mm, puberulent with curved trichomes to pilosulous. |
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 linear-lanceolate, 4–5 mm, apex acute, pilosulous to puberulent with curved trichomes; corolla pale green, campanulate, lobes ascending and exceeding corona segments, oval, (9–)12–15 mm, apex acute to obtuse, glabrous; gynostegium sessile; fused anthers brown and green, turbinate, 2.5–3 mm, wings shallowly trapezoidal, closed, apical appendages ovate, erose; corona segments pale to dark purple, upper margin usually white, sessile, clavate-tubular, 3–5 mm, greatly exceeded by style apex, deflexed at base, margins connivent, apex ascending to incurved, rounded, upper margin and cavity hirtellous, internal appendage a low internal crest, hirtellous; style apex shallowly depressed, green. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
broadly ovate, 5.5–7.5 × 4–6 mm, margin winged, obscurely erose at chalazal end, faces rugulose, minutely hirtellous; coma 2.5–4 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 upcurved pedicels, lance-ovoid to ovoid, 6–13 × (0.5–)1.2–3 cm, apex acuminate, shallowly rugose-ribbed, inconspicuously muricate apically on ribs, striate, pilosulous. |
Asclepias obovata |
Asclepias viridis |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering Jan–Nov; fruiting (Apr–)May–Nov. |
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, flats, glades, ravines, fields, pastures, hammocks, ditches, shale, limestone, granite, sandstone, silty, sandy, rocky, clay, and calcareous soils, prairies, mesquite-juniper grasslands, oak-hickory, pine-oak, and riparian woodlands, oak forests, forest edges and openings. |
Elevation | 0–200 m. (0–700 ft.) | 0–600 m. (0–2000 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
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AL; AR; FL; GA; IA; IL; IN; KS; KY; LA; MO; MS; NE; OH; OK; TN; TX
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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 viridis is similar only to its sister species, A. asperula. The broader leaves with broader apices and corona segments that are less than half the length of the corolla lobes readily distinguish A. viridis from A. asperula. These species are also largely segregated edaphically: A. viridis on deeper, valley soils and A. asperula on rocky, upland soils. Hybrids between A. viridis and A. asperula subsp. capricornu have been documented at several locations in northern Texas and southern Oklahoma. Both species flower early in that region (April–May) and may re-flower sporadically through the summer in response to disturbance from fire or mowing, with a second peak of flowering in the fall when weather conditions are favorable. Asclepias viridis displays an unusual distribution. Outside of the tall- and mixed-grass prairies of the southern Great Plains, where it is most abundant, it occupies glade habitats across the eastern United States, extending to chalk prairies in the southeastern states and pine rocklands in southern Florida. It is rare at the margins of its range and is considered to be of conservation concern in Indiana (Clark and Harrison counties) and West Virginia (Jackson and Wirt counties). Recently, it has been documented to occur in Iowa, close to the Missouri state line in Ringgold County. (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 | Acerates paniculata, Anantherix paniculata, A. viridis, Asclepiodora viridis, Podostigma viride | |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 321. (1817) | Walter: Fl. Carol., 107. (1788) |
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