354 ASCLEPIADACE^. (miLKWEED FAMILY.) 



purple ; hoods of the crown (flesh-color) ovate, about the length of the ascend- 

 ing or scythe-form awl-shaped horns; pods veiny, smooth. — Varies with the 

 leaves a little heart-shaped at the base, and, in var. piIlchra, with broader and 

 shorter-petioled leaves, more or less hairi/-pubescent, as well as the stem. (A. 

 pulchra, Willd.) — Wet grounds; the smooth form very common northward; 

 the hairy variety raore so southward. July, Aug. — Milky juice scanty. 

 -1- ■*- Leaves alternate-scattered, or the lowest opposite : milh/ juice little or none. 



13. A. tuberdsa, L. (Butteefly-weed. Pleukisy-koot.) Rough- 

 ish-hairy ; stems erect or ascending, veiy leafy, branching at the summit, and 

 bearing the umbels in a tei-minal corymb ; leaves varying from linear to oblong- 

 lanceolate, sessile or slightly petioled ; divisions of the corolla ovate-oblong 

 (greenish-orange) ; hoods of the crown narrowly oblong, bright orange, scarcely 

 longer than the nearly erect and slender awl-shaped honis ; pods hoary. (A. 

 decimbens, L.) — Dry hills and fields ; common, especially southward. July— 

 Sept. — Plant 1°- 2° high, leafy to the summit, usually with numerous and 

 corymbed short-peduncled umbels of very showy flowers, which are rather 

 smaller than in No. 1 . 



-!-+-•<- Leaves nearly all whorled, rarely alternate, croioded. 



14. A. verticiUata, L. (Whorled Milkweed.) SmootLish ; stems 

 slender, simple or sparingly branched, minutely hoary in lines, very leafy to the 

 summit; leaves very narrowly lineai', with revolute margins (2' -3' long, 1" 

 wide), 3 - 6 in a whorl ; umbels small, lateral, and terminal ; divisions of the co- 

 rolla ovate (greenish-white) ; hoods of the crown roundish-oval, about half the 

 length of the incurved claw-shaped horns ; pods very smooth. — "Dry hills ; 

 common, especially southward. July -Sept. — Flowers small. 



2. ACERATES, Ell. Gkeen Milkweed. 



Nearly as in Asclepias; but the pollen-masses more slender, with longer 

 stalks, and the concave upright hoods of the crown destitute of a horn (whence 

 the name, from a privative and Kepas, -aros, a horn). 



1. A. viridifldra, Ell. Downy-hoary; stems low and stout, ascending; 

 leaves varying from oval or obovato to lanceolate or almost linear, slightly peti- 

 oled, mucronate-acute or obtuse, thick, at length smoothish ; umbels nearly sessile, 

 densely many-flowered, globose, lateral ; divisions of the corolla oblong ; hoods of 

 the crown oblong, strictly erect, sessile at the base of the tube of filaments, shoit- 

 er than the anthers ; pods nearly smooth. (Asclepias viridiflora, Pursh. A. 

 lanceolata, Ives. A. obovata. Ell.) — Dry hills and sandy fields ; common, es- 

 pecially southward. July -Sept. — Flowers greenish; when expanded, about 

 the length of the pedicel. Leaves singularly variable in form. 



2. A. longifolia, Ell. Minutely hoary or rough-hairy; stem slender, up- 

 right (1°-2J° high) ; leaves elongated-linear (3'-7' long, i'-J' wide) ; umbels 

 peduncled, open, many-flowered ; divisions of the corolla ovatc-oblong, several 

 times shorter than the pedicels ; hoods of the crown short and rounded, raised on 

 the tube ofJUaments; pods smooth. — Moist places, Ohio to Wisconsin and south- 

 ward. June, July. — Flowers half as large as in the last, tinged with yellowish 

 and purplish. 



