Asclepias viridiflora
Asclepias pedicellata
asclépiade à fleurs vertes, green antelopehorn milkweed, green comet milkweed, green milkweed
savanna milkweed, savannah milkweed
solitary, erect to ascending, unbranched (rarely), (10–)20–125 cm, puberulent with curved trichomes, not glaucous, rhizomes absent.
1, erect, unbranched, 10–45 cm, puberulent with curved trichomes, not glaucous, rhizomes absent.
opposite to subopposite, sessile or petiolate, with 1 or 2 stipular colleters on each side of petiole and also in axil;
petiole 0–5 mm, puberulent with curved trichomes;
blade linear to broadly oval or nearly orbiculate, 2–13 × 0.8–6 cm, chartaceous, base cuneate to rounded, margins entire or crisped, apex acute or obtuse to truncate or emarginate, mucronate, venation brochidodromous, surfaces sparsely pilosulous to glabrate, margins ciliate, laminar colleters absent.
opposite, sessile, with 1 stipular colleter on each side of leaf base;
blade linear to narrowly elliptic or narrowly lanceolate, 1.5–6 × 0.1–0.8 cm, chartaceous, base cuneate, margins entire, apex acute, mucronate, venation obscure to eucamptodromous, surfaces puberulent with curved trichomes or scabridulous to glabrate, margins ciliate, 2 laminar colleters.
extra-axillary at upper nodes, sometimes branched at peduncle apex, sessile or pedunculate, 22–60-flowered;
peduncle 0–4 cm, puberulent with curved trichomes to pilosulous, with 1 caducous bract at the base of each pedicel.
terminal and extra-axillary at upper nodes, pedunculate, 2–7-flowered;
peduncle 0.15–1 cm, densely puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel.
7–13 mm, pilosulous.
5–13 mm, minutely puberulent with curved trichomes.
erect to pendent;
calyx lobes narrowly lanceolate, 2–3 mm, apex acute, pilosulous;
corolla green to yellowish green, sometimes tinged red, lobes reflexed, oblong, 5–7 mm, apex acute, inconspicuously pilosulous at apex abaxially, glabrous adaxially;
gynostegium sessile;
fused anthers green, cylindric, 3–4 mm, wings triangular, widest at middle, closed, apical appendages ovate, marginally inflexed, apically deflexed;
corona segments green to cream, sometimes tinged red, sessile, laminar, margins incurved, appressed to column, 3–4 mm, greatly exceeded by style apex, apex obtuse, glabrous, internal appendage absent or obscure, glabrous;
style apex shallowly depressed, green.
erect;
calyx lobes elliptic, 2–3 mm, apex acute, sparsely puberulent with curved trichomes to glabrate;
corolla yellowish green to green, lobes erect, mostly concealing corona, narrowly elliptic, 7–10 mm, apex acute, glabrous;
gynostegial column 4–6 mm;
fused anthers green, broadly conic, 1–1.5 mm, wings right-triangular with decurrent base, closed, apical appendages ovate;
corona segments yellowish green to green, sometimes dark green at apex, sessile, conduplicate, 1.5–2.5 mm, greatly exceeded by style apex, apex incurved, rounded, glabrous, internal appendage absent;
style apex flat, green.
ovate, 7–8 × 4–5 mm, margin winged, faces minutely rugulose;
coma 2.5–3 cm.
ovate, 5–6 × 3–4 mm, margin winged, faces sparsely and minutely rugulose;
coma 2–2.5 cm.
erect on upcurved pedicels, fusiform to lance-ovoid, 6–10 × 1.5–2 cm, apex acuminate to attenuate, smooth, pilosulous.
erect on straight pedicels, fusiform, 8–14 × 0.3–0.5 cm, apex long-attenuate, smooth, densely puberulent with curved trichomes.
= 22.
Asclepias viridiflora
Asclepias pedicellata
Asclepias viridiflora is one of the milkweeds with spherical, greenish umbels and inconspicuous coronas (see also A. engelmanniana, A. hirtella, A. lanuginosa, A. longifolia, A. rusbyi, A. stenophylla). Prior to close examination, the tight green balls of open flowers appear to be merely in bud. The diversity in leaf morphology among individuals (linear to orbiculate) is remarkable, but has no taxonomic significance—the full range of variation may be found within single populations. This is the most widespread milkweed within the flora area, ranging across most of the United States (absent only from the westernmost states and most of New England) and southern Canada. It is nowhere abundant, but may be regularly encountered in suitable, thin-soiled prairie habitats, especially in the Great Plains. It is rare and considered to be of conservation concern on the margins of its range, in Alberta (Cypress, Forty Mile, and Warner counties), Arizona (Coconino, Gila, and Yavapai counties), Connecticut (New Haven County), Florida (Gadsden and Jackson counties), and New York (Columbia, Nassau, Richmond, and Suffolk counties).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Asclepias pedicellata is found in drier habitats than some co-distributed milkweeds, such as A. connivens and A. viridula. It sometimes occurs in the same sites as A. cinerea, A. curtissii, and A. feayi. The erect petals and elongate gynostegial column are unique among Asclepias species in the flora area. The green flowers with hidden coronas and low stature of the plants can make them frustratingly cryptic in their grass-dominated habitats. Asclepias pedicellata is common only in Florida and North Carolina and is considered rare and of conservation concern in the intervening region in Georgia and South Carolina.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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