Asclepias obovata |
Asclepias latifolia |
|
---|---|---|
pineland milkweed |
broad-leaf milkweed, corn-kernel milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1 (rarely more), erect to spreading, unbranched, 40–70(–200) cm, densely hirtellous to velutinous, not glaucous, rhizomes absent. |
1–10, erect, unbranched, 25–100 cm, puberulent with curved trichomes or thinly tomentose to glabrate, sometimes glaucous, rhizomatous. |
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 1–4 stipular colleters on each side of petiole, sometimes also in axil; petiole 0–4 mm, thinly tomentose to glabrate; blade oval or oblong to ovate or orbiculate, 5.5–14 × 3–14 cm, subsucculent to coriaceous, base cordate, sometimes clasping, margins entire, apex truncate to rounded, sometimes emarginate, mucronate, venation brochidodromous, surfaces thinly tomentose to glabrate, sometimes glaucous, margins minutely ciliate to glabrous, 24–80 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, sessile or pedunculate, 20–59-flowered; peduncle 0–2.5 cm, puberulent with curved trichomes to pilosulous, with 1 caducous bract at the base of each pedicel. |
Pedicels | 10–12 mm, densely hirtellous to velutinous. |
15–35 mm, densely tomentose to glabrate. |
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 pendent; calyx lobes lanceolate, 4–5 mm, apex acute, tomentose to glabrate; corolla green, lobes reflexed, elliptic to oval, 7–9 mm, apex acute, glabrous abaxially, papillose at base adaxially; gynostegial column 1–1.5 mm; fused anthers green, cylindric, 3–3.5 mm, wings right-triangular, closed, apical appendages ovate; corona segments cream, sometimes dorsally yellow, aging yellow, stipitate, conduplicate, dorsally rounded, 3–5.5 mm, equaling to slightly exceeding style apex, apex truncate, oblique, papillose, internal appendage falcate, exserted, sharply inflexed over style apex, papillose; style apex shallowly depressed, green. |
Seeds | broadly ovate, 8–9 × 6–7 mm, margin winged, faces smooth; coma 2–5 cm. |
ovate, 7–8 × 5–6 mm, winged, faces minutely rugulose to smooth; coma 3–4 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, ovoid, 6.5–9.5 × 2–3 cm, apex obtuse to apiculate, smooth, minutely pilosulous to thinly tomentulose. |
2n | = 22. |
|
Asclepias obovata |
Asclepias latifolia |
|
Phenology | Flowering May–Sep; fruiting Jul–Oct. | Flowering May–Sep; fruiting Jun–Oct. |
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, dunes, canyons, arroyos, terraces, springs, ditches, limestone, shale, sandstone, caliche, silty, clay, sandy, rocky, and gravel soils, prairies, shrubby and mesquite grasslands, pastures, desert scrub, pinyon-juniper, juniper, and riparian woodlands, pine forests. |
Elevation | 0–200 m. (0–700 ft.) | 400–2300 m. (1300–7500 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; OK; SC; TX
|
AZ; CO; KS; NE; NM; OK; TX; UT; Mexico (Chihuahua, Coahuila)
|
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 latifolia is a distinctive species of the western Great Plains and Colorado Plateau, rising above short grasses and appearing as squat, leafy pagodas. It is most likely to be confused with A. arenaria (which is restricted to sandy substrates) due to the overlapping leaf shapes and floral colors of these species. Asclepias latifolia favors clayey, often rocky soils, but can be found also on sandy soils, especially on the Colorado Plateau, outside the range of A. arenaria. These species can be distinguished by habit (erect in A. latifolia versus erect to decumbent in A. arenaria), vestiture (more uniformly and persistently hairy in A. arenaria), petioles (absent or nearly so in A. latifolia versus present in A. arenaria), and the flower and seed characters included in the key. Asclepias speciosa in the absence of reproductive structures is also commonly confused with A. latifolia, but the leaves of A. speciosa are distinctly petiolate, persistently hairy, and typically taper to the apex. There is an apparent gap in the distribution of A. latifolia on the eastern Colorado Plateau, in northwestern New Mexico and southwestern Colorado, but the disjunct portions of the range are not accompanied by phenotypic divergence. Asclepias latifolia is limited in Nebraska to southwestern counties (Deuel, Dundy, Franklin, and Hayes), but it is apparently not uncommon there. Likewise, it is common in its limited range in Utah (Garfield, Grand, Kane, San Juan, and Wayne counties). (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. obtusifolia var. latifolia | |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 321. (1817) | (Torrey) Rafinesque: Atlantic J. 1: 146. (1832) |
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