Asclepias obovata |
Asclepias nummularia |
|
---|---|---|
pineland milkweed |
tuft 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, unbranched, 6–15 cm, taller on vegetative or post-reproductive plants, densely tomentose 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, petiolate, with 1 stipular colleter on either side of petiole; petiole 3–4 mm, tomentose to glabrate; blade orbiculate to obovate or oblate, 1.5–3.2 × 1.7–4 cm, much larger on vegetative or post-reproductive stems, subsucculent, base rounded to cordate, margins entire, apex truncate or emarginate to rounded or obtuse, venation eucamptodromous, surfaces tomentose to glabrate, laminar colleters 0–10. |
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, sometimes also extra-axillary, pedunculate, 5–28-flowered; peduncle 2.7–6 cm, tomentose, with 1 bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
12–20 mm, densely pilosulous to tomentulose. |
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 ovate to lanceolate, 1.5–2.5 mm, apex acute, pilose to tomentulose; corolla pinkish violet to tan, striate, lobes reflexed, oval, 4–5 mm, apex acute, glabrous abaxially, minutely papillate at base adaxially; gynostegial column 0.2–0.5 mm; fused anthers brown, cylindric, 1–1.5 mm, wings curved, closed, apical appendages ovate, erose; corona segments white apically, red-violet basally, sessile, conduplicate, dorsally rounded, 2.5–3 mm, equaling or exceeding style apex, apex truncate, glabrous, internal appendage falcate, exserted, sharply inflexed over style apex, glabrous; style apex shallowly depressed, cream to pink. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
broadly ovate, 6–7 × 4–5 mm, margin winged, corky, erose at chalazal end, faces papillose-rugulose, hirtellous; coma 1.5–2.5 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, lance-ovoid, 4–7.5 × 1.2–1.5 cm, apex long-acuminate, smooth, tomentose. |
Asclepias obovata |
Asclepias nummularia |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering Mar–May; fruiting May–Aug. |
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. | Hills, slopes, ridges, flats, arroyos, canyons, rhyolite, granite, sandstone, limestone, igneous outcrops, rocky, gravel, sandy, chalky, or clay soils, oak, oak-juniper, pinyon-juniper, and riparian woodlands, pine-oak forests, desert and oak grasslands. |
Elevation | 0–200 m. (0–700 ft.) | 1100–1900 m. (3600–6200 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
|
AZ; NM; TX; n Mexico; c Mexico
|
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 nummularia is the only milkweed in the flora area with small stature and obovate to orbiculate leaves that are bluish under dense tomentum until late in the season. The plants often bear an uncanny resemblance to tiny cabbages. Fruit set may fail across broad regions in some years, perhaps due to drought, although the adequacy of pollination in this species has not been studied. Unlike many species of Asclepias, post-reproductive and non-reproductive plants of A. nummularia often persist until frost. Coupled with the early flowering of this species, vegetative plants are observed and collected far more often than reproductive ones. Some plants persisting into the fall months have much larger leaves and longer stems, especially in shady or moist habitats; these have often been mistaken for A. latifolia, the range of which only barely overlaps that of A. nummularia in Grant County, New Mexico. Asclepias nummularia is not common in New Mexico, where it has been found in Grant, Hidalgo, and Sierra counties, and is only locally common in Texas in the Davis Mountains (Jeff Davis County), and additionally in Brewster and Presidio counties. Populations from San Luis Potosí and south with narrower leaves have been segregated as A. nummularioides W. D. Stevens; recognition of this taxon requires further evaluation. (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) | Torrey in W. H. Emory: Rep. U.S. Mex. Bound. 2(1): 163, plate 45, fig. A. (1859) |
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