Asclepias sullivantii
Asclepias lemmonii
asclépiade de Sullivant, prairie milkweed, Sullivant's milkweed
big-leaf milkweed, Lemmon's milkweed
solitary, erect, unbranched, 55–90 cm, glabrous, glaucous, rhizomatous.
1–3, erect to ascending, unbranched, very stout, 100–150 cm, densely hirsute, 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 1–5 mm, hirsute;
blade oval or oblong to ovate, 7–22 × 3–14 cm, subsucculent, base truncate to subcordate, margins entire, apex obtuse to truncate or emarginate, mucronate, venation brochidodromous, secondary veins nearly orthogonal, surfaces hirsute, margins ciliate, 8–16 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, paired, and extra-axillary, pedunculate, 21–53-flowered;
peduncle 6–13 cm, densely hirsute, with 1 caducous bract at the base of each pedicel.
22–36 mm, glabrous, glaucous.
13–22 mm, densely hirsute.
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, 3.5–6 mm, apex acute, hirsute;
corolla cream to greenish cream or ochroleucous, sometimes tinged pink, lobes reflexed with spreading tips, elliptic, 9–11 mm, apex acute, glabrous;
gynostegial column 0.5–1 mm;
fused anthers greenish brown, cylindric, 2.5–3 mm, wings right-triangular, closed, apical appendages oval;
corona segments cream to ochroleucous, sometimes tinged pink, shiny, subsessile, conduplicate, 6–8 mm, equaling or exceeding style apex, apex truncate, spreading and tapering, glabrous, internal appendage laterally compressed, erect, barely exserted, glabrous;
style apex shallowly depressed, green or pink.
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 4–4.5 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, 9.5–13.5 × 2–3 cm, apex attenuate, smooth, densely hirsute.
= 22.
Asclepias sullivantii
Asclepias lemmonii
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.)
A highly distinctive species, Asclepias lemmonii just barely enters the United States in southern Arizona (Cochise, Pima, and Santa Cruz counties), where it inhabits canyons in pine-oak clad sky-island ranges. Asclepias elata is a common co-inhabitant of these canyons. Asclepias lemmonii has been documented from the Baboquiviri, Chiricahua, Huachuca, and Santa Rita mountains, and it is not common in any of these. It is considered to be of conservation concern in Arizona. The large, hirsute leaves with nearly orthogonal venation and robust, hirsute stems of A. lemmonii are unmatched among American milkweeds. Plants may reach heights over 2 m in the main range of the species in the northern Sierra Madre Occidental.
(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
