Wood. J J- 40 [June 18, 



union of cells without connecting tubes, genuflexuous ; cytiodeini 

 somewhat thick, infolded at the ends ; spores elliptical. 

 Diam. cell, steril. 7/05"=. 0012. 



GEN. MESOCARPUS. 

 M. SCALARI8. Hassal. 

 Hab. In stagnis prope Philadelphia. 



ORD. SIPHOPHYCEAE. 

 FAM. HYDROGASTRE^. 

 GEN. HYDEOGASTRUM. 

 H. GKANiJLATUM. {Linn). Disv. 

 Hab. In stagnis exsiccatis, Delaware. Dr. I. F. Billings, 



FAM. YAUCHERIACE^E. 



GEN. VAUCHERIA. 



V. GEMiNATA. ( Vauch). De C. 

 Hab, In stagnis prope Philadelphia. 



V. POLTMORPHA. 8p. NoV. 



Y. in caespites dense intricata ; thallo capillari, tenui ; antheridia cor- 

 niculata ex ramuli lateralis apice formatis ; raraulis fertilibus interdum 

 et oogoniis et antheridiis instructis, interdum antlieridiis solum ; oogoniis 

 plerumque geminis, interdum singulis, globosis vel ovatis, ssepe brevi- 

 rostratis, plerumque distincte pedunculatis sed rarius sessilibus ; oosporis 

 enormiter subglobosis vel ovatis; sporodermate achroo e stratis duobus 

 composite. 



Csespitose ; thallus hair like, thin ; antheridia corniculate, formed of 

 the apex of lateral branches ; fertile branches sometimes furnished both 

 with oogonia and antheridia, sometimes with antheridia alone ; oogonia 

 sometimes single but mostly in pairs, occasionally shortly rostrate, gen- 

 erally distinctly pedunculate but sometimes sessile ; oospores irregularly 

 subglobose or ovate, surrounded by a transparent double spore coat. 



Hab. In aquis prope "Buffalo Bayou," Louisiana. Prof. H. W. 

 Ravenel. 



V. SERICEA. Lyngb. 

 Hab. In stagnis et liumis irroratis prope Philadelphia. 



V. AVERSA. Hassal. 

 Bemarks. — I have found this species in the neighborhood of Philadel- 

 phia, if indeed it be a species. Prof. Rabenhorst thinks it probably 

 merely a form of the preceeding and all the specimens I have seen 

 appeared to run into it. 



