124 



ASCLEPIADACE.E. 



ACERATES. 



2. ACERATES. Ell. sk. 1. <p. 316 ; E?idl. gen. 3488 ; Decaisne in DC. prodr. 8. p. 521. 

 [ From the Greek, a, privative, and keras, a horn ; the stamineal crown being without horns.] 



Calyx 5-parted. Corolla deeply 5-parted ; the limb spreading or reflexed. Stamineal crown 

 5-parted ; the lobes erect or curved, concave, without an awn. Anthers terminated by a 

 membrane. Pollen-masses clavated, suspended by their slender attenuated summit. Styles 

 slender. Stigma flattish-depressed. Follicles smooth or muricate. — Herbs with the habit 

 of Asclepias, from which they differ chiefly in wanting the horns of the nectary. Flowers 

 mostly greenish. 



1. Ace rates viridiflora, Ell. (PI. LXXXVIII.) Green-jlowered Silkweed. 



Stem erect or ascending, pubescent ; leaves varying from ovate or obovate to lanceolate, 

 rather thick, pubescent on both sides, nearly sessile ; umbels somewhat globose, many- 

 flowered, almost sessile, nodding ; segments of the corolla oblong, reflexed ; lobes of the 

 crown oblong, equalling the stamineal column. — Ell. sk. 1. p. 317 ; Decaisne in DC. prodr. 

 8. p. 522. Asclepias viridiflora, Raf. in med. repos. 11. p. 360; Pursh, jl. 1. p. 181 ; 

 Torr. Jl. 1. p. 284 ; Bigel. jl. Bost. p. 104 ; Beck, hot. p. 237 ; Darlingt.fi. Cest. p. 174 ; 

 Hook.jl.Bor.-Am. 2. p. 53. t. 143. A. lanceolata, Ives in Sill. jour. 4. p. 252, with a plate. 

 A. obovata, Ell. sk. 1. p. 321. Polyotus heterophyllus, Nutt. in trans. Am. phil. soc. (n. 

 ser.) 5. p. 199. 



Stems often clustered, 1-2 feet high, rigid. Leaves 2-3 inches long and from half an 

 inch to an inch and a half or more in width, acute or obtuse, sometimes emarginate. Umbels 

 2-4 terminal and in the upper part of the stem, 1 - \\ inch in diameter, on very short thick 

 pubescent peduncles. Segments of the calyx lanceolate. Corolla greenish ; the oblong 

 segments reflexed close against the pedicel. Lobes of the crown appressed to the stamineal 

 column ; the lobes obtuse, not cucullate : horn entirely wanting. Pollen-masses much more 

 slender, and with a much longer neck, than in Asclepias. Follicles 3-4 inches long, 

 lanceolate, somewhat ventricose, nearly smooth ; the point long and tapering. 



Dry hills and sandy fields : southern part of the State. July. 



