184 STNGENESIA. KECESSARIA. 



nute radial florets; rays emarcinate, each connected at tl^e 

 base \vitl> 2 masculine sheathed florets, f Style of the 

 imperfect discal florets entire. 



Species. 1. P. mtegrifoUxnn. A second species of this 

 genus with a low and decumbent stem and subpinnatifid 

 villous leaves k^ows around St. Lutiis, Louisiana, and a 

 third very distinct from No, 1. also exists in the open fo- 

 rests of Tennessee; but of these I possess neither notes 

 noisspecimens. 



A North American genus with the exception of one 

 species in the warmer parts of America. 



599. CHRYSOGONUM. Z. 



Calix 5-lcaYC(]. Receptacle paleaceous. Pap- 

 pus 1 -leaved, 3-tootiied. Seed surrounded by a 

 4-leaved calicle. 



A low herbaceous plant with opposite leaves; flowers 

 mostly terminal, yellow. 



Species. C. virginiamim. The only species of the 

 genus. 



600. BALTIMORA. X. 



Calix cylindric, many-leaved, Rays 5, Rc- 

 . ceptacle paleaceous* Fappus none. Seed tri- 

 quetrous. 



Herbaceous; leaves oppos'.te, asperate, S-iicrvcd, flow- 

 el's subpaniculated, terminal. 



Species. B. i-ectn. -f- Probably as Mr. T'ursh remark.=, 

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

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

 hty. 



601. GYMNOSTYLES. Jussieu. ■ 



Calix niaiiy-leaved, tlic Iraflets disposed in a 

 single order. Feminine f: or cts apctalous. Seeds 

 compressed, partly toothed at the summit, awn- 

 ed with the persistent style. 



Small and partly stem less herbaceous plants with dif- 

 fuse branchlets; flowers solitary and sessile. 



f A somewhat similar arrangement appears to exist in Silphi- 

 wn pumihm to which this genus is allied. 



