Asclepias longifolia
Asclepias macrotis
Florida milkweed, long-leaf milkweed
long-hood milkweed, longhorn milkweed
1–few, spreading to decumbent, unbranched, 25–70 cm, puberulent with curved trichomes, not glaucous, rhizomes absent.
few–numerous, erect to ascending, branched at base, 10–35 cm, minutely puberulent with curved trichomes in a line to glabrate, not glaucous, rhizomatous.
opposite or alternate, sessile or petiolate, with 1 or 2 stipular colleters on each side of petiole, also in axil;
petiole 0–2 mm, puberulent with curved trichomes;
blade linear to linear-lanceolate, 5–18 × 0.2–1 cm, chartaceous, base cuneate, margins entire, apex acute to attenuate, sometimes mucronate, venation brochidodromous, surfaces scabridulous to puberulent with curved trichomes, especially on veins, margins ciliate, laminar colleters absent.
opposite, sessile, with 1 stipular colleter on each side of leaf base;
blade filiform, 2.5–7 × 0.05–0.15 cm, membranous, base cuneate, margins revolute, apex acute, mucronate, venation obscure, surfaces glabrous, margins minutely ciliate at base, laminar colleters absent.
terminal and extra-axillary at upper nodes, sessile or pedunculate, 13–28(–36)-flowered;
peduncle 0–6 cm, puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel.
extra-axillary, sessile or pedunculate, 2–7-flowered;
peduncle 0–0.8 cm, puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel.
9–16 mm, puberulent with curved trichomes.
6–10 mm, minutely puberulent with curved trichomes in a line.
erect to spreading;
calyx lobes narrowly lanceolate, 1.5–2 mm, apex acute, puberulent with curved trichomes;
corolla white to greenish cream, purple at lobe tips, lobes reflexed, oblong, 3–5 mm, apex obtuse, glabrous;
gynostegial column 0.2–0.5 mm;
fused anthers green or brown, cylindric, 1–1.5 mm, wings triangular to trapezoidal, widest at middle, slightly open at tip, apical appendages ovate;
corona segments pinkish lavender to red-violet, often with white apex, often a darker red-violet stripe or at base, sessile, laminar, strongly dorsally compressed, margins incurved, appressed to column, curved to subsaccate, 2–2.5 mm, exceeding point of anther wings, greatly exceeded by style apex, apex obtuse to truncate, glabrous, internal appendage absent or obscure, glabrous;
style apex shallowly depressed, greenish cream to green.
erect;
calyx lobes lanceolate, 2–2.5 mm, apex acute, glabrous;
corolla greenish cream tinged with red, lobes reflexed with spreading tips, oval, 4–5 mm, apex acute, glabrous;
gynostegial column 0.5–1 mm;
fused anthers brown, cylindric, 1–1.5 mm, wings right-triangular, closed, apical appendages broadly ovate;
corona segments cream to greenish cream, reddish brown at base or as a dorsal stripe, subsessile, conduplicate, 4–5 mm, exceeding style apex, apex truncate, long-caudate, crisped, with a proximal tooth on each side, hirtellous, internal appendage falcate, exserted, inflexed towards style apex, hirtellous;
style apex shallowly depressed, green.
ovate, 11–12 × 7–8 mm, margin winged, faces smooth;
coma 4–5 cm.
ovate, 6–8 × 2.5–4 mm, margin thickly winged, faces rugulose;
coma 2–2.5 cm.
erect on upcurved pedicels, narrowly fusiform, 8–13.5 × 0.7–1.2 cm, apex attenuate, smooth, puberulent with curved trichomes.
erect on upcurved pedicels, fusiform, 4.5–6 × 0.5–0.7 cm, apex attenuate, smooth, glabrous.
Asclepias longifolia
Asclepias macrotis
Asclepias longifolia has sometimes been treated to include A. hirtella as conspecific, as discussed under that species. As circumscribed here, the distribution of A. longifolia extends along the Atlantic Coastal Plain south of Delaware to Florida and westward to the Mississppi River. Reports of A. longifolia from west of the Mississippi River in Louisiana and in Texas are assigned here to A. hirtella. Hence, the range of A. longifolia in Louisiana is extremely limited, and the conservation status of this species warrants assessment in that state (Livingston, Saint Helena, Saint Tammany, Tangipahoa, and Washington parishes). Reports of A. longifolia from Maryland and West Virginia have not been confirmed, and the species is considered extirpated from Delaware. Otherwise, it is rare at the northern extent of its range and considered to be of conservation concern in North Carolina and Virginia (Greensville and Prince George counties).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
With a suffruticose, cespitose, intricately branched habit, the only other milkweed with which Asclepias macrotis can be confused is the rarely encountered A. sperryi, which is restricted to the Big Bend region of Texas in the flora area. Although A. macrotis ranges across western Texas, it appears to be absent from Big Bend; no mixed populations of these species are known, and hybridization is neither known nor suspected. Its distribution in Colorado is limited to the southeastern corner of the state and in Oklahoma to the extreme tip of the Panhandle, in Cimarron County. In Arizona, it is more common but limited to the three southeastern counties: Cochise, Pima, and Santa Cruz. The elongate, curled apices of the corona segments are unique, and the small, drab flowers are quite elegant.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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