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Mead's milkweed

asclépiade belle, showy milkweed

Habit Herbs. Herbs.
Stems

1 (rarely 2), erect, unbranched, 20–80 cm, glabrous, glaucous, rhizomatous.

1–few, erect, unbranched (rarely branched), 30–125 cm, tomentose to puberulent with curved trichomes, not glaucous, rhizomatous.

Leaves

opposite, sessile, with 1 stipular colleter on each side of petiole;

blade ovate to lanceolate, 4.5–10 × 1–5 cm, chartaceous, base rounded to obtuse, margins entire, apex acute, venation brochidodromous, surfaces glabrous, glaucous, margins inconspicuously ciliate, laminar colleters absent.

opposite, petiolate, with 1 or 2 stipular colleters on each side of petiole, sometimes also in axil;

petiole 4–12 mm, tomentose to pilose;

blade lanceolate or ovate to oblong, 6–20 × 2–14 cm, chartaceous, base rounded to truncate or cordate, margins entire, apex acute to obtuse, sometimes mucronate, venation faintly brochidodromous, surfaces tomentose to pilose, margins ciliate, 6–32 laminar colleters.

Inflorescences

terminal, rarely branched, pedunculate, 7–19-flowered;

peduncle (0–)3–10 cm, sparsely pilosulous to glabrate, glaucous, with 1 caducous bract at the base of each pedicel.

extra-axillary, pedunculate, 3–34-flowered;

peduncle 1–10 cm, densely tomentose, with 1 caducous bract at the base of each pedicel.

Pedicels

11–20 mm, pilosulous.

13–30 mm, densely tomentose.

Flowers

pendent;

calyx lobes narrowly lanceolate, 4–5 mm, apex acute, pilosulous;

corolla green to greenish cream, sometimes tinged red, lobes reflexed with spreading tips, oval, 7–9 mm, apex acute, glabrous;

gynostegial column 1.5–1.8 mm, fused anthers green, truncately obconic, 2–2.5 mm, wings right-triangular, closed, apical appendages ovate;

corona segments green to yellowish green or greenish cream, sessile, conduplicate, dorsally rounded, 4–5.5 mm, greatly exceeding style apex, base saccate, apex obtuse, emarginate, slightly flared, glabrous, internal appendage falcate, exserted, sharply inflexed towards style apex, glabrous;

style apex shallowly depressed, green.

erect to pendent;

calyx lobes elliptic, 4–8 mm, apex acute, tomentose;

corolla dark pink (rarely pale), lobes reflexed with spreading tips, elliptic, 9–12 mm, apex acute, densely pilose abaxially, hirtellous at base adaxially;

gynostegial column 0.5–1 mm;

fused anthers green and brown, truncately obconic, 2.5–3 mm, wings right-triangular, open, widely so at base, apical appendages deltoid;

corona segments pale pink to nearly cream, sessile, scoop-shaped, 9–15 mm, exceeding style apex, apex truncate with proximal tooth on each side and long-attenuate, flared, glabrous, internal appendage subulate, exserted, sharply inflexed over style apex, glabrous;

style apex shallowly depressed, green to cream or pink.

Seeds

ovate, 6–7 × 4–5 mm, winged, faces coarsely papillose;

coma 3–4.5 cm.

ovate, 7–9 × 4–5 mm, margin winged, faces rugulose;

coma 2.5–3 cm.

Follicles

erect on upcurved pedicels, narrowly fusiform, 7–14 × 0.9–1.6 cm, apex long-acuminate, smooth to minutely rugulose, puberulent with curved trichomes.

erect on upcurved pedicels, lance-ovoid, (5–)9–12 × 2–3 cm, apex long-attenuate, muricate or smooth, densely tomentose.

2n

= 22.

Asclepias meadii

Asclepias speciosa

Phenology Flowering May–Jun(–Jul); fruiting Jun–Aug. Flowering (Apr–)May–Sep; fruiting Jul–Oct.
Habitat Dry, upland prairies, chert-lime glades. Slopes, flats, hills, valleys, canyons, coulees, streamsides, lake and pond edges, ditches, swales, seeps, granite, basalt, schist, pumice, serpentine, alluvium, clay, sandy, silty, rocky, and saline soils, pine and mixed-conifer forests, oak and pine woodlands, chaparral, riparian woods, shrubby and non-native grasslands, prairies, meadows, agricultural fields.
Elevation 100–500 m. (300–1600 ft.) 0–2600 m. (0–8500 ft.)
Distribution
from FNA
IA; IL; IN; KS; MO; WI
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; IA; ID; IL; KS; MI; MN; MO; MT; ND; NE; NM; NV; OK; OR; SD; TX; UT; WA; WI; WY; AB; BC; MB; SK [Introduced in e Europe]
[WildflowerSearch map]
[BONAP county map]
Discussion

With respect to historical range reduction and potential threats, Asclepias meadii is the most endangered North American milkweed species and is considered to be of conservation concern in each of the states in which it occurs. Nearly all of the viable populations are now restricted to Missouri and eastern Kansas; many of these are found in hay meadows, in which fruit maturation does not occur. Asclepias meadii is endemic to the highly-impacted tallgrass prairie ecoregion and is thought to be rare as a result of habitat loss. Consequently, concern for the continued existence of this species can be considered emblematic of concern for the tallgrass prairie as a whole. Active recovery efforts have achieved limited success, with newly established populations experiencing high mortality and slow growth of transplants. It has been re-introduced to Indiana and Wisconsin, but long-term survival of these populations is uncertain. The sessile, glaucous leaves and pendent umbels on a long peduncle suggest a diminutive version of A. elata; however, these species do not appear to be closely related (Fishbein et al. 2011). The terminal inflorescence of pendent umbels is unique among tallgrass prairie milkweeds.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Asclepias speciosa is the western counterpart of A. syriaca; both are broad-leaved species with large umbels of pinkish flowers. The distinctive, large, tapering corona segments, which form the broadest corona span of any American species of Asclepias, immediately distinguish A. speciosa from A. syriaca. These species hybridize extensively from Minnesota and southern Manitoba to Kansas, blurring the distinctions in the zone of contact, which corresponds roughly to the transition from tallgrass to mixed-grass prairie (R. P. Adams et al. 1987b). Not every individual in this zone can be readily assigned to one species or the other. This is the most extensive hybrid zone in North American Asclepias. These hybrids have also been documented in Illinois, far to the east of the contact zone. Possible hybrids with A. eriocarpa and A. hallii in California are discussed under those species. Outside of its contiguous range in the West, A. speciosa is known from a few sporadic, mostly historical records from Illinois, Michigan, Missouri, and Wisconsin. Most, if not all, of these records represent adventive, ephemeral outposts from the native range.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 14. FNA vol. 14.
Parent taxa Apocynaceae > Asclepias Apocynaceae > Asclepias
Sibling taxa
A. albicans, A. amplexicaulis, A. angustifolia, A. arenaria, A. asperula, A. brachystephana, A. californica, A. cinerea, A. connivens, A. cordifolia, A. cryptoceras, A. curassavica, A. curtissii, A. cutleri, A. eastwoodiana, A. elata, A. emoryi, A. engelmanniana, A. eriocarpa, A. erosa, A. exaltata, A. fascicularis, A. feayi, A. hallii, A. hirtella, A. humistrata, A. hypoleuca, A. incarnata, A. involucrata, A. labriformis, A. lanceolata, A. lanuginosa, A. latifolia, A. lemmonii, A. linaria, A. linearis, A. longifolia, A. macrosperma, A. macrotis, A. michauxii, A. nummularia, A. nyctaginifolia, A. obovata, A. oenotheroides, A. ovalifolia, A. pedicellata, A. perennis, A. prostrata, A. pumila, A. purpurascens, A. quadrifolia, A. quinquedentata, A. rubra, A. rusbyi, A. ruthiae, A. sanjuanensis, A. scaposa, A. solanoana, A. speciosa, A. sperryi, A. stenophylla, A. subulata, A. subverticillata, A. sullivantii, A. syriaca, A. texana, A. tomentosa, A. tuberosa, A. uncialis, A. variegata, A. verticillata, A. vestita, A. viridiflora, A. viridis, A. viridula, A. welshii
A. albicans, A. amplexicaulis, A. angustifolia, A. arenaria, A. asperula, A. brachystephana, A. californica, A. cinerea, A. connivens, A. cordifolia, A. cryptoceras, A. curassavica, A. curtissii, A. cutleri, A. eastwoodiana, A. elata, A. emoryi, A. engelmanniana, A. eriocarpa, A. erosa, A. exaltata, A. fascicularis, A. feayi, A. hallii, A. hirtella, A. humistrata, A. hypoleuca, A. incarnata, A. involucrata, A. labriformis, A. lanceolata, A. lanuginosa, A. latifolia, A. lemmonii, A. linaria, A. linearis, A. longifolia, A. macrosperma, A. macrotis, A. meadii, A. michauxii, A. nummularia, A. nyctaginifolia, A. obovata, A. oenotheroides, A. ovalifolia, A. pedicellata, A. perennis, A. prostrata, A. pumila, A. purpurascens, A. quadrifolia, A. quinquedentata, A. rubra, A. rusbyi, A. ruthiae, A. sanjuanensis, A. scaposa, A. solanoana, A. sperryi, A. stenophylla, A. subulata, A. subverticillata, A. sullivantii, A. syriaca, A. texana, A. tomentosa, A. tuberosa, A. uncialis, A. variegata, A. verticillata, A. vestita, A. viridiflora, A. viridis, A. viridula, A. welshii
Name authority Torrey ex A. Gray: Manual ed. 2, 704. (1856) Torrey: Ann. Lyceum Nat. Hist. New York 2: 218. (1827)
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