18G9.] 1^'^ [Wood. 



B. sparsely branched, elongate with the jomts H-2^ times longer 

 than broad (y^^oo"=.0066) ; oosporangia soinetimes lateral and sessile, 

 sometimes placed upon the apex of a branch, sometimes situated 

 in the length of the branches between their cells ; the empty cell which 

 supports them without dissepiment ; oospores oval, filling closely the 

 cavity of the spore case, longitudinally somewhat obliquely and distantly 

 costate ; spore coat rather thick ; antheridia 3-4 celled, scarcely stipate. 



Hab. In aquis quietis prope Philadelphia. 



FAM. CHAETOPHORACEAE. 



GEN. CHAETOPHORA. 

 c. PisiFOKMis {Roth) Ag. 

 Hab. In stagnis plantas, &c., adhaereus prope. Philadelphia. 



GEN. DRAPARNALDIA. 

 D. PLUMOSA. ( Yauch.) Ag. 

 Hab. In aquis quietis prope Philadelphia. 



D. GLOMERATA. {VcVUch.) Ag. 



Hab. In rivulis et stagnis et aquis limpidis quietis prope Philadelphia. 



D. BILLINGSII. 8p. Nov. 



D. valde gelatinosa; fills et ramis primariis achrois ad yf-^o" crassis, 

 sparsissime ramosis, articulis diametro 2-6 plo longioribus, saepe medio 

 valde tumidis ; fasciis chlorophyllis dilute viridibus, saepe nuUis aut 

 subnullis ; ramulorum fasciculis distantibus, late ovalibus vel late trian- 

 gularibus, alternantibus vel oppositis vel tripio verticellatis, sparse 

 ramosis, patentissimis ; ramulis cum pila longissima robusta terminale ; 

 oosporis globosis, moniliforme conju^nctis ; sporodermate crasso. 



Frond very gelatinous, filament and primary branches attaining a diam- 

 eter of 2 so"' very sparsely branched, their articles 2-6 times longer than. 

 broad, often very much swollen in the middle ; chrorophyll band light 

 green, frequently almost or entirely wanting ; fascicles of branches 

 distant, broadly oval or triangular, alternate, opposite or in whorls of 

 three, very open ; ultimate branchlets terminating in a long, robiist, 

 hyaline hair ; resting spores globose, with thick walls, arranged in long 

 moniliform sometimes branched filaments. 



Remarks. — I dedicate this very beautiful species to Dr. J. S. Billings, 

 TJ. S. A., to whom I am under the greatest obligations for aid in the 

 prosecution of this research, and whom I have ever found to unite the 

 greatest scientific liberality to a strong enthusiasm for and able prosecu- 

 tion of the study of these lower vegetable forms. 



Hab. In aquis limpidis quietis prope Philadelphia. 



GEN. APHANOCHAETE. 



A. KEPENs. A. Braun. 



Hab. In algiis confervaceis prope Philadelphia. 

 A. P. S. — VOL. XI — S 



