Asclepias sullivantii
Asclepias emoryi
asclépiade de Sullivant, prairie milkweed, Sullivant's milkweed
Emory's milkweed
solitary, erect, unbranched, 55–90 cm, glabrous, glaucous, rhizomatous.
1–4, erect to spreading, unbranched or rarely branched near base, 6–30 cm, puberulent with curved trichomes to hirtellous, 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.
persistent or gradually caducous from base, opposite, sessile or petiolate, with 1 stipular colleter on each side of petiole;
petiole 0–17 mm, puberulent with curved trichomes to hirtellous;
blade elliptic to lanceolate or lance-ovate, 3–7.5 × 0.4–2.5 cm, chartaceous, base cuneate, margins often crisped, apex acute, venation eucamptodromous, surfaces hirtellous, usually conduplicate, laminar colleters absent.
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.
extra-axillary, sessile or pedunculate, 4–8-flowered;
peduncle 0–2 cm, hirtellous, with 1 caducous bract at the base of each pedicel.
22–36 mm, glabrous, glaucous.
7–10 mm, hirtellous.
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;
calyx lobes linear-lanceolate to narrowly elliptic, 3–4 mm, apex acute, hirtellous;
corolla green, sometimes tinged red or brown, faintly striate, lobes reflexed, elliptic, 5–7 mm, apex acute, hirtellous throughout or glabrate at tips abaxially, glabrous adaxially;
gynostegial column 0.5–1 mm;
fused anthers green, obconic, 1–1.5 mm, wings trapezoidal, closed, apical appendages ovate;
corona segments proximally green, distally white or cream, sessile, tubular, 3.5–5.5 mm, greatly exceeding style apex, apex flared, deeply emarginate, minutely papillose, internal appendage lingulate, sharply incurved, at the same level as and closing the segment apex, minutely papillose.
ovate, 7–9 × 5–6 mm, margin winged, faces minutely rugulose;
coma 3.5–4.5 cm.
oval, 7 × 5–6 mm, margin winged, faces smooth;
coma 2.5–3.5 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, lance-ovoid, 5–9 × 1.2–2 cm, apex attenuate to acuminate, smooth, puberulent with curved trichomes to hirtellous, sometimes faintly striate.
= 22.
Asclepias sullivantii
Asclepias emoryi
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 emoryi is distributed entirely within the range of its close relative, A. oenotheroides. Distinguishing them is discussed under the latter species. A few putative hybrid specimens have been collected. These can be distinguished from A. emoryi by slightly longer corona segments (usually shorter than in A. oenotheroides) with sinuate apices, slightly longer corolla lobes, and slightly broader leaves. Although not accorded conservation concern, A. emoryi is very rarely encountered (across its entire range) and merits study for evaluation of needed protections. Reports of A. emoryi from New Mexico are based upon misidentifications. It is restricted in the flora area almost entirely to southern Texas, but there are a few scattered occurrences to the northwest.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
IL Wildflowers
KS Wildflowers
MI Flora
MN Wildflowers
MO Plants
WildflowerSearch
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