184 SYNGENESIA. NECESSARIA. 



nute radial florets; rays emarginate, each connected at tlie 

 base with 2 masculine sheathed florets, f Style of the 

 imperfect discal florets entire. 



Speci'es. 1. V. ijitegrifoUum. A second species of this 

 genus with a low and decumbent stem and subpinnatifid 

 villous leaves grows around bt. Louis, Louisiana, and a 

 third very distinct i'rom No. 1. also exists in tlie open fo- 

 rests of Tennessee; but of these I possess neither notes 

 nor specimens. 



A North American genus with the exception of one 

 species in the warmer parts of America. 



599. CHRYSOGONUM. X. 



Calix 5-Ieavt'(h Receptacle paleaceous. Pap- 

 pus 1 leaver], S-toothed. Seed surrounded by a 

 4-leaved calirle. 



A low herbaceous plant with opposite leaves; flowers 

 mostly terminal, yellow. 



Spicies. C. ■virginianum. The only species of the 

 genus. 



600. BALTIMORA. X. 



Calix cylindric, many-leaved. IRatjs 5. Be- 

 ceptacle paleaceous, Fappus none. Seed tri- 

 quetrous. 



Herbaceous; leaves opposite, asperate, S-nerved, flow- 

 ers subpaniculated, terminal. 



Species. B. recta, -f- Probably as Mr. Pursh remarks, 

 not indigenous to the United States. —Of this genus there 

 is a second species with white flowers, of uncertain loca- 

 lity. 



601. GYMNOSTYLES. Jussieu. 



Calix many -leaved, the leaflets disposed in a 

 sini^le order. Feminine Jlorets apetalous. Seeds 

 compressed, partly tootlied at the summit, awn- 

 cd NNith the persistent style. 



Small and jjartly stemless herbaceous plants with dif- 

 fuse branchlets; flowers solitary and sessile. 



•f A somewhat similar arrangement appears to exist in Sllp/n 

 vmpximilum to which this genus is allied 



