Asclepias cordifolia
Asclepias quinquedentata
heart-leaf milkweed, purple milkweed
slim-pod milkweed
1–20, ascending to spreading, unbranched, 25–100 cm, glabrous, glaucous, rhizomes absent.
1–5, erect to ascending, sometimes decumbent at base, unbranched or branched near base, 10–60 cm, sparsely puberulent with curved trichomes to glabrate, not glaucous, rhizomes absent.
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 or petiolate, with 1 or 2 stipular colleters on each side of petiole;
petiole 0–1 mm, puberulent with curved trichomes to glabrate;
blade linear, 6–14 × 0.2–0.6 cm, membranous, base cuneate, margins entire, apex acute, mucronate, venation obscure to faintly eucamptodromous, surfaces sparsely puberulent with curved trichomes on midvein to glabrate, margins ciliate, 0–2 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, the uppermost appearing terminal, pedunculate, 4–10-flowered (appearing greater because umbels are in close proximity);
peduncle 1.1–2.7 cm, sparsely puberulent with curved trichomes, with 1 bract at the base of each pedicel.
16–37 mm, sparsely pilose.
14–21 mm, puberulent with curved trichomes.
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.
pendent to spreading;
calyx lobes lanceolate, 2.5–3.5 mm, apex acute, strigulose to pilosulous;
corolla green, sometimes tinged red, lobes reflexed, exposing corona, oval, 4–6 mm, apex acute, pilose abaxially, glabrous adaxially;
gynostegial column 0.5 mm;
fused anthers tan to brown, cylindric, 1.5–2 mm, wings narrowly right-triangular, slightly open at base, apical appendages ovate;
corona segments red or pink to red-violet or purple at base, white at apex, shiny, sessile, conduplicate, dorsally rounded, 3–4 mm, equaling to slightly exceeding style apex, apex truncate with a proximal tooth on each side, glabrous, internal appendage a crest, barely exserted from cavity;
style apex shallowly depressed, white to greenish.
ovate, 8–9 × 5–7 mm, margin not winged, faces reticulate-rugulose;
coma 3–3.5 cm.
ovate, 4–5 × 3–4 mm, margin winged, faces smooth;
coma 2–2.5 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, fusiform, 8.5–16 × 0.5–1 cm, apex long-attenuate, smooth, faintly striate, pilosulous to glabrate.
= 22.
Asclepias cordifolia
Asclepias quinquedentata
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.)
Although it is widely distributed, Asclepias quinquedentata is rarely encountered. The plant is cryptic, even in flower, because of the slender, few-leaved habit and nodding inflorescences. Nonetheless, it appears to truly be rare, at least in the United States. It is considered to be of conservation concern in Arizona, and its status in New Mexico requires evaluation. It has been reported from Texas, based on the presumed type locality. However, M. Fishbein et al. (2008) concluded that the type collection most likely was made in Arizona. The population in the Valle de México has been segregated as A. rzedowskii based on a subtle variant of the corona; it is here considered a synonym (Fishbein et al.).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
