





I 



Vol. 35 



BULLETIN 



No 3 



OF THE 



TORREY BOTANICAL CLUB 



MARCH, 1908 



Studies in the North American Convolvulaceae— IV. The 



p 



genus Exogonium 



Homer Doliver House 

 (with plates i and 2) 



I porno e a bracteata Cav., 

 and with several other West Indian species 



M 



forms one of the natural groups of species usually referred to 

 pomoea. The group is recognized as a genus by Peter and by 



Pu 



Ipomoea by Grisebach and by Meis 



ip 



not all the members possess the salverform corolla and exserted 



stamens of /. Purga, and should more properly be retained in 



pomoea. Until very recently the genus was regarded as almost 



wholly confined to the West Indies. Recent collections in 



Mexico 



Indi 



is occur in Mexico, 

 tifoliuM, of the West 



les. 



EXOGONIUM Choisy, Mem. Soc. Phys. Genev. 6: 443- 



1833. — In DC. Prodr. 9: 346. 1845 



Perennial, trailing or twining vines, usually with woody stems. 

 Leaf-blades entire or lobed. Flowers several on axillary peduncles 

 0r solitary ; bracts large and colored, sometimes inconspicuous 

 0r absent. Sepals membranaceous or subherbaceous, equal or 

 Ur >equal, never awned. Corolla scarlet or white ; the tube often 

 slender and constricted at the throat or expanding above in a 

 salverform or funnelform limb. Stamens and style exserted or 

 Protruding, rarely included. Ovary 2-celled, 4-ovuled. Capsules 

 °^° ld » thick -walled, apiculate. Seeds with a long coma of hairs 



[The Bulletin for February, 1908 (35 : 49-96), was issued 9 Mr 1908.] 



97 



