Asclepias cordifolia
Asclepias sullivantii
heart-leaf milkweed, purple milkweed
asclépiade de Sullivant, prairie milkweed, Sullivant's milkweed
1–20, ascending to spreading, unbranched, 25–100 cm, glabrous, glaucous, rhizomes absent.
solitary, erect, unbranched, 55–90 cm, glabrous, glaucous, rhizomatous.
opposite, sessile, stipular colleters absent;
blade ovate to lanceolate, 3.5–11 × 1.8–8 cm, chartaceous, base cordate, clasping, margins entire, apex acute, mucronate, venation brochidodromous to eucamptodromous, surfaces glabrous, glaucous, margins minutely ciliate, laminar colleters 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.
terminal, branched, sometimes also extra-axillary at upper nodes, pedunculate, 5–20-flowered;
peduncle 0.3–6.5 cm, apically sparsely pilose to glabrate, with few bracts.
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.
16–37 mm, sparsely pilose.
22–36 mm, glabrous, glaucous.
erect to pendent;
calyx lobes elliptic to lanceolate, 3–5 mm, apex acute, pilose;
corolla red-violet, lobes reflexed with spreading tips, oval, 6–7 mm, apex acute, glabrous;
gynostegial column 1–1.5 mm;
fused anthers brown, cylindric, 1.5–2 mm, wings right-triangular, open at tip, apical appendages deltoid;
corona segments white, tinged pink to red-violet at base, sessile, tubular, 2–3 mm, exceeded by style apex, base saccate, apex truncate, oblique, glabrous, internal appendage absent;
style apex shallowly depressed, pink to red-violet.
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.
ovate, 8–9 × 5–7 mm, margin not winged, faces reticulate-rugulose;
coma 3–3.5 cm.
ovate, 7–9 × 5–6 mm, margin winged, faces minutely rugulose;
coma 3.5–4.5 cm.
erect on upcurved pedicels, lance-ovoid, 7.5–10.5 × 1.5–1.8 cm, apex long-acuminate, smooth, glabrous, glaucous.
erect on upcurved pedicels, lance-ovoid, 7–11 × 1.5–3 cm, apex acuminate, sparsely muricate, sparsely pilosulous to glabrate, glaucous.
= 22.
= 22.
Asclepias cordifolia
Asclepias sullivantii
Fresh leaves and stems of Asclepias cordifolia are often slightly or strongly colored bluish, grayish, or purplish. This is one of the few American species of Asclepias with cavitate corona segments that lack adaxial appendages. Such species were segregated along with diverse African species in Gomphocarpus R. Brown, a polyphyletic segregate (M. Fishbein et al. 2011; D. Chuba et al. 2017). Asclepias cordifolia is a distinctive species unlike any other within its range. It is phylogenetically and geographically isolated, although not highly derived morphologically. In Nevada, A. cordifolia is restricted to the Sierra Nevada, in Carson City, Douglas, and Washoe counties. Its range extends to northern California and southwestern Oregon.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
IL Wildflowers
KS Wildflowers
MI Flora
MN Wildflowers
MO Plants
