Asclepias longifolia
Asclepias purpurascens
Florida milkweed, long-leaf milkweed
asclépiade pourpreé, purple milkweed
1–few, spreading to decumbent, unbranched, 25–70 cm, puberulent with curved trichomes, not glaucous, rhizomes absent.
1, erect, unbranched, 50–120 cm, puberulent in lines with curved trichomes, 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 (rarely whorled at 1 midstem node), petiolate, with 1 or 2 stipular colleters on each side of petiole, also in axil;
petiole 4–18 mm, puberulent with curved trichomes;
blade ovate or oval to lanceolate or elliptic, 6–20 × 2–10 cm, chartaceous, base cuneate, margins entire, apex obtuse to acute, apiculate, or mucronate, venation eucamptodromous to faintly brochidodromous, surfaces pilosulous, sparsely so adaxially, margins ciliate, 12–20 laminar colleters.
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.
terminal, branched, also usually extra-axillary, sessile or pedunculate, 17–72-flowered;
peduncle 0–7 cm, puberulent with curved trichomes to pilosulous, with 1 caducous bract at the base of each pedicel.
9–16 mm, puberulent with curved trichomes.
12–28 mm, puberulent with curved trichomes.
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 to spreading;
calyx lobes lanceolate, 3–5 mm, apex acute, puberulent with curved trichomes;
corolla reddish purple, lobes reflexed with spreading tips, elliptic, 7–10 mm, apex acute, glabrous abaxially, papillose at base adaxially;
gynostegial column 1–1.5 mm;
fused anthers brown, cylindric, 2–2.5 mm, wings broadly right-triangular, closed to slightly open at tip, apical appendages ovate;
corona segments reddish purple, stipitate, conduplicate with a lateral flange on each side, 5–6 mm, greatly exceeding style apex, apex acute, glabrous, internal appendage falcate, exserted, sharply inflexed over style apex, glabrous;
style apex shallowly depressed, red-violet to green.
ovate, 11–12 × 7–8 mm, margin winged, faces smooth;
coma 4–5 cm.
ovate, 7–8 × 4–5 mm, margin winged, faces rugulose;
coma 3–4 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, lance-ovoid, 10–16 × 1.5–2.5 cm, apex long-acuminate, smooth, puberulent with curved trichomes.
Asclepias longifolia
Asclepias purpurascens
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.)
Asclepias purpurascens is most common in rocky uplands of the Ozark Mountains and the piedmont of the northern Appalachian Mountains. Its reddish purple flowers are extremely showy and the species merits cultivation. The flowers have a strong cinnamon scent. Similarities to A. variegata and A. exaltata are discussed under those species. Although widespread in eastern North America, A. purpurascens is now rare over most of its range and has experienced a significant loss of populations and habitat everywhere but the Ozarks. It is considered to be of conservation concern in Connecticut, Delaware, Georgia (Floyd and Murray counties), Louisiana (Caldwell and Lincoln parishes), Maryland, Massachusetts, Michigan, Mississippi (Grenada and Washington counties), Nebraska (Nemaha and Richardson counties), New York, North Carolina, Tennessee, Virginia, and Ontario (Chatham-Kent, Essex, and Lambton counties). Moreover, it is presumed extirpated from the District of Columbia, Minnesota, New Hampshire, and Rhode Island. It has been reported, but not verified, from Maine and Vermont and, if historically present, is now extirpated there as well. Hybrids with A. amplexicaulis, A. exaltata, and A. syriaca have been documented from the New England and mid-Atlantic regions where A. purpurascens is now rare or extirpated. Putative hybrids exhibit intermediate floral and vegetative characteristics.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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