﻿Vail: Studies in the Asclepiadaceae. 31 



[Otanema Raf. 1. c. 61. 1836.] 



Erect or procumbent perennial herbs. ^ Stems simple or 

 branched. Leaves opposite, alternate or scattered. Inflorescence 

 umbelliform, sessile or peduncled, terminal and lateral, several to 

 many-flowered. Peduncles subtended by numerous involucrai 

 bracts. Flowers greenish or occasionally purplish-tinged. Calyx 

 small, 5-parted, the segments acute, usually bi-glandulose at the 

 sinus. Corolla rotate, deeply 5-parted, the segments small, reflexed 

 in anthesis. Column very short, not always apparent, with com- 

 monly S^ l ° small glands or processes alternating with the anther- 

 wings. Hoods mostly attached over the whole of the column, 

 erect, equalling or shorter than the anthers, involute-concave and 

 somewhat pitcher-shaped, often pendulous and saccate at the base, 

 entire, emarginate or 2-3-lobed or toothed at the apex, the ventral 

 margins spreading towards the base into broad auricles or small 

 infolded concealed lobes, either destitute of horns or crests or in two 

 species with rudimentary ones. Anther-wings angulate about or 

 somewhat below the middle, narrowed and rounded towards the 

 base or rarely of the same width from the apex downwards, entire 

 or notched. Follicles on erect or recurving pedicels. Otherwise as 

 in Asclepias. 



Seven species are known from the United States and three 

 more are said by Eugene Fournier (Ann. Sci. Nat. Ser. 6, 14 : 386. 

 1882.) to occur in Mexico. 



Key to tlie Species. 



Auricles of the hood when present concealed within. 

 Umbel solitary, terminal. 

 Umtels several, lateral, (in no. 2 occasionally terminal). 



I. A. lanuginosa. 



Hoods rounded, much shorter than the anthers, entire at the summit. 



2. A. Floridana. 



Hoods entire, rounded or acutish at the summit, as high as the anthers. 



Hoods 2-parted at the summit, the divisions lanceolate. 



3. A. viridiflora . 



4. A. bifida. 



Auricles of the hood conspicuously spreading; umbels lateral. 



Hoods emarginate or truncate at the summit, crestless within. 



5. A. auriculata. 

 Hoods 3-lobed at the summit, with an internal crest-like midrib, terminating in 



6. A. angustifolia. 



the middle lobe. 



Hoods truncate and entire at the summit, with an obscure, thin horn attached to 

 the keel of the hood and nearly reaching its apex. 



7. A. Rusbyi. 



