354 ASCLEPIADACEvE. (MILKWEED FAMILY.) 



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

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

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

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

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

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

 *- *- Leaves alternate-scattered, or the lowest opposite, : milky juice little or none. 



13. A. tufoerosa, L. (BUTTERFLY-WEED. PLEURISY-ROOT.) Rough- 

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

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

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

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

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

 decumbens, 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 . 



- -i- -t- Leaves nearly all whorled, rarely alternate, crowded. 



14. A. verticillata, L. (WHORLED MILKWEED.) Smoothish ; stems 

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

 summit; leaves very narrowly linear, 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. GREEX MILKWEED. 



Nearly as in Asclepias ; but the concave upright hoods of the crown desti- 

 tute of a horn (whence the name, from a privative and nepac, -aroc, a horn). 



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

 leaves varying from oval or obovate 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, short- 

 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- 

 light (l-2^ high) ; leaves elongated-linear (3' -7' long, i'-' wide) ; umbel* 

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

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

 the tube of filaments; pods smooth. Moist places, Ohio to Wisconsin and south- 

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



A. MONOCEPHALA and A. PANICULATA ; see Addend. 



