MONOPETALOUS EXOGENOUS PLANTS. 449 



gined, the upper ones small and remote ; umbels 2-5, 

 corymbose, 6-10-flowered ; pedicels pubescent, about as 

 long as the peduncle ; corolla deep red; leaves of the crown 

 oblong, erect, bright orange, more than twice as long as 

 the subulate incurved horn and the short-stalked gynoste- 

 gium; /b//ic/e lanceolate, minutely pubescent. June and 

 July. Stem 2°-4'' high ; leaves 6-12' long ; corolla 3"-4" 

 long. In marshes and low places. 



ttt Upper and lower leaves mostly opposite, the middle ones wTix/rled. 



A. QUADRiFOLiA, Jacq. Somcwhat pubescent; stem 

 slender, simple ; leaves thin, ovate or ovate-lanceolate, acu- 

 minate, contracted into a petiole, pale beneath ; umbels 

 2-5 f many-flowered, the slender peduncle longer than the 

 pedicels ; corolla pale pink; leaves of the crown white, ob- 

 long, obtuse, twice as long as the gynostegium and stout 

 horn. June-August. Stem l°-l-2-° high; leaves 2-3' 

 long. 



tttt Leaves altei'nate, or the lowest opposite. 



A. TUBEROSA, L. Hirsute; stem erect or declining, 

 widely branched above, very leafy ; leaves varying from 

 linear to oblong, acute, short-petioled ; umbels numerous, 

 corymbose; ^oroZZ« yellowish orange; leaves of the crown 

 bright orange, erect, oblong-lanceolate, twice as long as the 

 gynostegium, and rather longer than the slender incurved 

 horn. Light dry soil, common. June and July. Stem 

 l°-2° long. Bed Eiver. 



A. SPECIOSA. Eed Kiver. — Torrey. 



ACERATES, Ell. 



Leaves of the crown destitute of a horn-like appendage. 

 Otherwise like Asclepias. 



* Leaves opposite. 



A. YiRiDiFLORA, Ell, Pubescent ; stem stout, simple ; 



