34 ASCLEPIADACEAE. Vou, III. 
3. ACERATES Ell. Bot. S. C. & Ga. 1: 316. 1817. 
Perennial herbs, similar to Asclepias, with alternate or opposite thick leaves, and green 
or purplish flowers in terminal or axillary and short-peduncled or- sessile umbels. Calyx 
5-parted or 5-divided, the segments acute, glandular within. Corolla deeply 5-cleft, the seg- 
ments valvate, reflexed in anthesis, Corona-column very short. Corona of 5 involute-concave 
or somewhat pitcher-shaped hoods, neither horned nor crested within or in one species having 
a small interior crest and usually a few small processes at the base of the anther-wings, 
forming an obscure inner crown. Pollen-masses solitary in each sac, oblong, pendulous, 
Stigma 5-lobed. [Greek, without horn, referring to the crown.] 
About 7 species, natives of North America. Type species: Acerates longifolia (Michx.) Ell. 
Umbels sessile, or very nearly so, mostly axillary. 
Leaves oval to linear; hoods entire at the apex. # . 1. A. viridiflora, 
Leaves narrowly linear ; hoods 3-toothed. 2. A, angustifolia, 
Umbels, at least the lower, distinctly peduncled. 
Plants glabrous, or nearly so; umbels usually several; leaves narrow. 
Hoods obtuse, entire; column 14” long; stem roughish puberulent. 
Hoods emarginate; column very short; stem glabrous. 
Plant hirsute ; umbel solitary, terminal; leaves ovate to oblong. 
. A, floridana, 
. A, auriculata, 
A, lanuginosa, 
ae 
1. Acerates viridiflora (Raf.) Eaton. Green Milkweed. Fig. 3409. 
Asclepias viridiflora Raf. Med. Rep. (II.) 5: 360. 1808, 
Acerates viridiflora Eaton, Man. Ed. 5, 90. 1829. 
Puberulent or tomentulose, at least when young; 
stems simple, reclined or ascending, rather stiff, 
1°-3° high. Leaves slightly rough, alternate or op- 
posite, thick, oval, oblong or ovate to lanceolate or 
linear, 1’-5’ long, 4’-2’ wide, short-petioled, the mar- 
gins usually undulate; umbels several, or rarely 
solitary, axillary, densely many-flowered, sessile or 
very nearly so; pedicels very slender, tomentose, 
4’-8” long; flowers green; corolla-segments nar- 
rowly oblong, 2’-3” long; column very short or 
none; hoods lanceolate-oblong, obtuse, minutely 
2-auricled at the base; mass of anthers longer than 
thick; anther-wings tapering below, semi-rhomboid 
above; follicles puberulent, 2’-4’ long. 
In dry, sandy or rocky soil, Massachusetts to south- 
ern Ontario, Saskatchewan, Florida and Texas. Con- 
sists of several races, differing mainly in leaf-form. 
June-Sept. 
2. Acerates angustifolia (Nutt.) Dec. 
Narrow-leaved Milkweed. Fig. 3410. 
Polyotus angustifolius Nutt. Trans. Am, Phil. Soc. 
CII.) 5: 201. 1833-37. : 
A. angustifolia Dec. in DC, Prodr. 8: 522. 1844. 
Asclepias stenophylla A, Gray, Proc. Am, Acad, 12: 
72, 1876, 
Stems mostly several together, erect, straight, 
1°-2° high, puberulent above, glabrate below. 
Leaves opposite, or some of the lower alternate, 
sessile, narrowly linear, 2’-5’ long, glabrous, the 
revolute margins and the thick midvein rough 
beneath; umbels 1o-15-flowered, short-peduncled 
or subsessile, axillary, usually numerous; pedicels 
puberulent; corolla-segments oblong, greenish; 
hoods white, not exceeding the anthers, 3-toothed 
at the apex, the acute middle tooth merely a 
prolongation of the thickened crest-like midvein, 
shorter than the obtuse lateral ones; anther- 
wings notched at about the middle; follicles 
slender, erect, about 3’ long or more. 
On dry plains, Missouri, Nebraska and Colorado to 
Texas, 
