Asclepias obovata |
Asclepias emoryi |
|
---|---|---|
pineland milkweed |
Emory's milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1 (rarely more), erect to spreading, unbranched, 40–70(–200) cm, densely hirtellous to velutinous, not glaucous, rhizomes absent. |
1–4, erect to spreading, unbranched or rarely branched near base, 6–30 cm, puberulent with curved trichomes to hirtellous, 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. |
persistent or gradually caducous from base, opposite, sessile or petiolate, with 1 stipular colleter on each side of petiole; petiole 0–17 mm, puberulent with curved trichomes to hirtellous; blade elliptic to lanceolate or lance-ovate, 3–7.5 × 0.4–2.5 cm, chartaceous, base cuneate, margins often crisped, apex acute, venation eucamptodromous, surfaces hirtellous, usually conduplicate, 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, sessile or pedunculate, 4–8-flowered; peduncle 0–2 cm, hirtellous, with 1 caducous bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
7–10 mm, hirtellous. |
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 linear-lanceolate to narrowly elliptic, 3–4 mm, apex acute, hirtellous; corolla green, sometimes tinged red or brown, faintly striate, lobes reflexed, elliptic, 5–7 mm, apex acute, hirtellous throughout or glabrate at tips abaxially, glabrous adaxially; gynostegial column 0.5–1 mm; fused anthers green, obconic, 1–1.5 mm, wings trapezoidal, closed, apical appendages ovate; corona segments proximally green, distally white or cream, sessile, tubular, 3.5–5.5 mm, greatly exceeding style apex, apex flared, deeply emarginate, minutely papillose, internal appendage lingulate, sharply incurved, at the same level as and closing the segment apex, minutely papillose. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
oval, 7 × 5–6 mm, margin winged, faces smooth; coma 2.5–3.5 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, 5–9 × 1.2–2 cm, apex attenuate to acuminate, smooth, puberulent with curved trichomes to hirtellous, sometimes faintly striate. |
Asclepias obovata |
Asclepias emoryi |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering Mar–Aug(–Oct); fruiting Jul–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. | Plains, hills, slopes, limestone, caliche, sandy, clay, rocky, calcareous, and gravelly soils, prairies, mesquite grasslands, thorn scrub. |
Elevation | 0–200 m. (0–700 ft.) | 0–800 m. (0–2600 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
|
TX; Mexico (Coahuila, Nuevo León, San Luis Potosí, Tamaulipas) |
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 emoryi is distributed entirely within the range of its close relative, A. oenotheroides. Distinguishing them is discussed under the latter species. A few putative hybrid specimens have been collected. These can be distinguished from A. emoryi by slightly longer corona segments (usually shorter than in A. oenotheroides) with sinuate apices, slightly longer corolla lobes, and slightly broader leaves. Although not accorded conservation concern, A. emoryi is very rarely encountered (across its entire range) and merits study for evaluation of needed protections. Reports of A. emoryi from New Mexico are based upon misidentifications. It is restricted in the flora area almost entirely to southern Texas, but there are a few scattered occurrences to the northwest. (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 | Podostemma emoryi | |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 321. (1817) | (Greene) Vail in J. K. Small: Fl. S.E. U.S., 948. (1903) |
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