Asclepias sullivantii
Asclepias hypoleuca
asclépiade de Sullivant, prairie milkweed, Sullivant's milkweed
mahogany milkweed, talayote
solitary, erect, unbranched, 55–90 cm, glabrous, glaucous, rhizomatous.
1 (rarely 2 or 3), erect, unbranched, 25–100 cm, puberulent with curved trichomes to pilosulous, not glaucous, rhizomes absent.
opposite, sessile, with 1 or 2 stipular colleters on each side of leaf base;
blade lanceolate or ovate to oblong, 6.5–15 × 1.5–9 cm, succulent, base cordate, margins entire, apex obtuse to rounded or acute, sometimes emarginate, mucronate, venation brochidodromous, surfaces glabrous, glaucous, margins eciliate, 4–12 laminar colleters.
opposite, petiolate, with 1 stipular colleter on each side of petiole;
petiole 2–6 mm, puberulent with curved trichomes to pilosulous;
blade ovate or lanceolate to oblong, elliptic, or oval, 5.5–11.5 × 1–5 cm, chartaceous, base cuneate or obtuse to truncate, margins entire, apex obtuse to rounded, mucronate, venation eucamptodromous, surfaces tomentose abaxially, pilosulous or tomentulose to glabrate adaxially, margins ciliate, 8–12 laminar colleters.
extra-axillary at upper nodes, sometimes appearing terminal, pedunculate, 9–29-flowered;
peduncle 1–6 cm, glabrous, glaucous, with 1 caducous bract at the base of each pedicel.
terminal and extra-axillary, pedunculate, 12–35-flowered;
peduncle 3.5–10.5 cm, puberulent with curved trichomes to tomentulose, with 1 caducous bract at the base of each pedicel.
22–36 mm, glabrous, glaucous.
15–21 mm, densely puberulent with curved trichomes or pilosulous to tomentulose.
erect;
calyx lobes lanceolate, 4–5 mm, apex acute, glabrous, glaucous;
corolla dark pink, pale at base of lobes, lobes reflexed, sometimes with spreading tips, elliptic, 8–12 mm, apex acute, glabrous;
gynostegial column 1–1.5 mm;
fused anthers truncately green, obconic, 2.5–3.5 mm, wings narrowly right-triangular, open at base, apical appendages ovate;
corona segments pale to dark pink, subsessile, tubular, flattened dorsally, 5–7 mm, exceeding style apex, apex broadly obtuse, oblique, glabrous, internal appendage subulate, exserted, sharply inflexed over style apex, glabrous;
style apex shallowly depressed, green.
erect to pendent;
calyx lobes lanceolate, 3–4 mm, apex acute, pilose;
corolla green, sometimes red-tinged abaxially, deep maroon to greenish red or green adaxially, lobes reflexed, tips usually spreading, oblong to elliptic, 8–10 mm, apex acute, pilosulous abaxially, glabrous adaxially;
gynostegial column 1–1.5 mm;
fused anthers brown, broadly cylindric, 2–2.5 mm, wings right-triangular, open at tip, apical appendages ovate, erose;
corona segments deep maroon to greenish red or yellowish green, subsessile, conduplicate, 7–9 mm, greatly exceeding style apex, apex truncate, spreading and long-tapering with a proximal tooth on each side, glabrous, internal appendage absent or a low crest, glabrous;
style apex shallowly depressed, green.
ovate, 7–9 × 5–6 mm, margin winged, faces minutely rugulose;
coma 3.5–4.5 cm.
ovate, 6–7 × 4–5 mm, margin winged, faces minutely rugulose;
coma 3–3.5 cm.
erect on upcurved pedicels, lance-ovoid, 7–11 × 1.5–3 cm, apex acuminate, sparsely muricate, sparsely pilosulous to glabrate, glaucous.
erect on upcurved pedicels, fusiform, 9–11.5 × 1.2–1.4 cm, apex long-attenuate, smooth, sometimes faintly striate, pilosulous to tomentulose.
= 22.
Asclepias sullivantii
Asclepias hypoleuca
The distribution of Asclepias sullivantii is coextensive with the tallgrass prairie, where it favors moist sites. The broad, smooth, glaucous, clasping leaves, often with pink venation, are similar only to A. amplexicaulis in the region, but the latter species favors dry sites and has a long, terminal peduncle. Because of the tremendous reduction in the extent and quality of tallgrass prairie, A. sullivantii is presumed to be less common than in former times and is considered to be rare and of conservation concern in Michigan, Minnesota, Wisconsin, and Ontario (Chatham-Kent, Elgin, Essex, Lambton, and Middlesex counties). It may be extirpated from North Dakota (historically in Cass and Richland counties) and South Dakota (historically in Clay, Lincoln, and Union counties). In Nebraska, it is limited to the eastern one-third of the state. Nonetheless, it is encountered commonly in suitable habitat along roadsides in the core of its range, in Illinois and Kansas. Asclepias sullivantii commonly co-occurs with and is often mistaken for A. syriaca from a distance but is easily distinguished by its smaller stature, ascending leaves, and the concentration of umbels at the apex of the stem, in addition to the glabrous and glaucous herbage that can be observed with closer examination. It is known to hybridize rarely with A. syriaca, and presumed hybrids can be recognized by intermediate vegetative and floral features.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Asclepias hypoleuca grows at higher elevations in the sky-island mountain ranges than any other milkweed. It has been documented from the Chiricahua, Huachuca, Rincon, Santa Catalina, Santa Rita, and White mountain ranges in Arizona (Cochise, Pima, and Santa Cruz counties) and the Mogollon Mountains and Black Range in New Mexico (Catron and Grant counties). Because of its limited, high-elevation distribution, and the threats of changing climate, its conservation status in the flora area merits assessment. The bicolored leaves exhibit coloration similar to co-occurring silverleaf oak (Quercus hypoleucoides).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
IL Wildflowers
KS Wildflowers
MI Flora
MN Wildflowers
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
