Asclepias meadii |
Asclepias pedicellata |
|
---|---|---|
Mead's milkweed |
savanna milkweed, savannah milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1 (rarely 2), erect, unbranched, 20–80 cm, glabrous, glaucous, rhizomatous. |
1, erect, unbranched, 10–45 cm, puberulent with curved trichomes, not glaucous, rhizomes absent. |
Leaves | opposite, sessile, with 1 stipular colleter on each side of petiole; blade ovate to lanceolate, 4.5–10 × 1–5 cm, chartaceous, base rounded to obtuse, margins entire, apex acute, venation brochidodromous, surfaces glabrous, glaucous, margins inconspicuously ciliate, laminar colleters absent. |
opposite, sessile, with 1 stipular colleter on each side of leaf base; blade linear to narrowly elliptic or narrowly lanceolate, 1.5–6 × 0.1–0.8 cm, chartaceous, base cuneate, margins entire, apex acute, mucronate, venation obscure to eucamptodromous, surfaces puberulent with curved trichomes or scabridulous to glabrate, margins ciliate, 2 laminar colleters. |
Inflorescences | terminal, rarely branched, pedunculate, 7–19-flowered; peduncle (0–)3–10 cm, sparsely pilosulous to glabrate, glaucous, with 1 caducous bract at the base of each pedicel. |
terminal and extra-axillary at upper nodes, pedunculate, 2–7-flowered; peduncle 0.15–1 cm, densely puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel. |
Pedicels | 11–20 mm, pilosulous. |
5–13 mm, minutely puberulent with curved trichomes. |
Flowers | pendent; calyx lobes narrowly lanceolate, 4–5 mm, apex acute, pilosulous; corolla green to greenish cream, sometimes tinged red, lobes reflexed with spreading tips, oval, 7–9 mm, apex acute, glabrous; gynostegial column 1.5–1.8 mm, fused anthers green, truncately obconic, 2–2.5 mm, wings right-triangular, closed, apical appendages ovate; corona segments green to yellowish green or greenish cream, sessile, conduplicate, dorsally rounded, 4–5.5 mm, greatly exceeding style apex, base saccate, apex obtuse, emarginate, slightly flared, glabrous, internal appendage falcate, exserted, sharply inflexed towards style apex, glabrous; style apex shallowly depressed, green. |
erect; calyx lobes elliptic, 2–3 mm, apex acute, sparsely puberulent with curved trichomes to glabrate; corolla yellowish green to green, lobes erect, mostly concealing corona, narrowly elliptic, 7–10 mm, apex acute, glabrous; gynostegial column 4–6 mm; fused anthers green, broadly conic, 1–1.5 mm, wings right-triangular with decurrent base, closed, apical appendages ovate; corona segments yellowish green to green, sometimes dark green at apex, sessile, conduplicate, 1.5–2.5 mm, greatly exceeded by style apex, apex incurved, rounded, glabrous, internal appendage absent; style apex flat, green. |
Seeds | ovate, 6–7 × 4–5 mm, winged, faces coarsely papillose; coma 3–4.5 cm. |
ovate, 5–6 × 3–4 mm, margin winged, faces sparsely and minutely rugulose; coma 2–2.5 cm. |
Follicles | erect on upcurved pedicels, narrowly fusiform, 7–14 × 0.9–1.6 cm, apex long-acuminate, smooth to minutely rugulose, puberulent with curved trichomes. |
erect on straight pedicels, fusiform, 8–14 × 0.3–0.5 cm, apex long-attenuate, smooth, densely puberulent with curved trichomes. |
Asclepias meadii |
Asclepias pedicellata |
|
Phenology | Flowering May–Jun(–Jul); fruiting Jun–Aug. | Flowering Mar–Nov(–Dec); fruiting May–Oct. |
Habitat | Dry, upland prairies, chert-lime glades. | Flats, streamsides, sandhills, sandy soils, pine flatwoods, savannas, pine-palmetto and oak-palmetto scrubs, often following fires. |
Elevation | 100–500 m. (300–1600 ft.) | 0–100 m. (0–300 ft.) |
Distribution |
IA; IL; IN; KS; MO; WI
|
FL; GA; NC; SC
|
Discussion | With respect to historical range reduction and potential threats, Asclepias meadii is the most endangered North American milkweed species and is considered to be of conservation concern in each of the states in which it occurs. Nearly all of the viable populations are now restricted to Missouri and eastern Kansas; many of these are found in hay meadows, in which fruit maturation does not occur. Asclepias meadii is endemic to the highly-impacted tallgrass prairie ecoregion and is thought to be rare as a result of habitat loss. Consequently, concern for the continued existence of this species can be considered emblematic of concern for the tallgrass prairie as a whole. Active recovery efforts have achieved limited success, with newly established populations experiencing high mortality and slow growth of transplants. It has been re-introduced to Indiana and Wisconsin, but long-term survival of these populations is uncertain. The sessile, glaucous leaves and pendent umbels on a long peduncle suggest a diminutive version of A. elata; however, these species do not appear to be closely related (Fishbein et al. 2011). The terminal inflorescence of pendent umbels is unique among tallgrass prairie milkweeds. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Asclepias pedicellata is found in drier habitats than some co-distributed milkweeds, such as A. connivens and A. viridula. It sometimes occurs in the same sites as A. cinerea, A. curtissii, and A. feayi. The erect petals and elongate gynostegial column are unique among Asclepias species in the flora area. The green flowers with hidden coronas and low stature of the plants can make them frustratingly cryptic in their grass-dominated habitats. Asclepias pedicellata is common only in Florida and North Carolina and is considered rare and of conservation concern in the intervening region in Georgia and South Carolina. (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 | Podostigma pedicellatum | |
Name authority | Torrey ex A. Gray: Manual ed. 2, 704. (1856) | Walter: Fl. Carol., 106. (1788) |
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