Asclepias obovata |
Asclepias quinquedentata |
|
---|---|---|
pineland milkweed |
slim-pod milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1 (rarely more), erect to spreading, unbranched, 40–70(–200) cm, densely hirtellous to velutinous, not glaucous, rhizomes absent. |
1–5, erect to ascending, sometimes decumbent at base, unbranched or branched near base, 10–60 cm, sparsely 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. |
opposite, sessile or petiolate, with 1 or 2 stipular colleters on each side of petiole; petiole 0–1 mm, puberulent with curved trichomes to glabrate; blade linear, 6–14 × 0.2–0.6 cm, membranous, base cuneate, margins entire, apex acute, mucronate, venation obscure to faintly eucamptodromous, surfaces sparsely puberulent with curved trichomes on midvein to glabrate, margins ciliate, 0–2 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. |
extra-axillary, the uppermost appearing terminal, pedunculate, 4–10-flowered (appearing greater because umbels are in close proximity); peduncle 1.1–2.7 cm, sparsely puberulent with curved trichomes, with 1 bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
14–21 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. |
pendent to spreading; calyx lobes lanceolate, 2.5–3.5 mm, apex acute, strigulose to pilosulous; corolla green, sometimes tinged red, lobes reflexed, exposing corona, oval, 4–6 mm, apex acute, pilose abaxially, glabrous adaxially; gynostegial column 0.5 mm; fused anthers tan to brown, cylindric, 1.5–2 mm, wings narrowly right-triangular, slightly open at base, apical appendages ovate; corona segments red or pink to red-violet or purple at base, white at apex, shiny, sessile, conduplicate, dorsally rounded, 3–4 mm, equaling to slightly exceeding style apex, apex truncate with a proximal tooth on each side, glabrous, internal appendage a crest, barely exserted from cavity; style apex shallowly depressed, white to greenish. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
ovate, 4–5 × 3–4 mm, margin winged, faces smooth; coma 2–2.5 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, fusiform, 8.5–16 × 0.5–1 cm, apex long-attenuate, smooth, faintly striate, pilosulous to glabrate. |
Asclepias obovata |
Asclepias quinquedentata |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering Jun–Aug; 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. | Slopes, canyons, limestone, rhyolite, rocky soils, chaparral, pinyon-juniper and oak woodlands, pine and pine-oak forests. |
Elevation | 0–200 m. (0–700 ft.) | 1300–2600 m. (4300–8500 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
|
AZ; NM; Mexico (Chihuahua, Distrito Federal, Durango, San Luis Potosí, México) |
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.) |
Although it is widely distributed, Asclepias quinquedentata is rarely encountered. The plant is cryptic, even in flower, because of the slender, few-leaved habit and nodding inflorescences. Nonetheless, it appears to truly be rare, at least in the United States. It is considered to be of conservation concern in Arizona, and its status in New Mexico requires evaluation. It has been reported from Texas, based on the presumed type locality. However, M. Fishbein et al. (2008) concluded that the type collection most likely was made in Arizona. The population in the Valle de México has been segregated as A. rzedowskii based on a subtle variant of the corona; it is here considered a synonym (Fishbein et al.). (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. rzedowskii | |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 321. (1817) | A. Gray: Proc. Amer. Acad. Arts 12: 71. (1876) |
Web links |