1869.] l'*^ [Wood. 



ANABAENA GIGANTEA. Sp. Nov. 



A. tliallo nullo, trichomatibits singulis et numei'oso-consociatis, iiatan- 

 tibus, rectis, in aetate juveni spiraliter convolutis ; articulis plerumque 

 subglobosis, arete connexis, granulosis; cellulis perdurantibus interjectis, 

 articulis vegetativis subaequalibus utroque polo punctiforme incrassatis, 

 subsphaericis ; sporis subspliaericis. 



Thallus wanting; filaments occurring floating singly on water or in 

 great numbers, straight, but in the young state often spirally convolute ; 

 articles mostly subglobose, closely connected, granular, heterocysts sub- 

 sphaerical, interstitial, a very little larger than the vegetative cells, 

 thickened at each end in a punctiform manner; spore subsphaerical. 



Diam. Artie vegetat. max 2 5oVo^ Heterocysts 2oijj-j=.0005. 



Spor. at. T2V(To= Long. ^^i^^=.001. 



EemarJcs. — With the above anabaena was a Caelospliaerium, which 

 appears to be the G. duMum Grun. In no instance, however, was the 

 frond of nearly so great size as the European form is said to attain to. 



I have also recently identified the following plants, new to this continent. 



GEN. CLADOPHORA. 

 c. BRACHTSTELECHA. Rahenh. 

 Hab. In aquis prope Philadelphia. 



C FRACTA. Dillw. 



Hab. In flumine Schuylkill. 



Stated Meeting^ July 16, 1869. 



Present, eight members. 



Mr. Fraley, Yice-President, iu tlie Chair. 



A letter accejjting membership was received from John 

 Phillips, dated Oxford, England, June 12, 1869. 



A photograph for the Album was received from J. H. C. 

 Coffin, of the National Observatory, Washington, D. C. 



Letters of invoice and acknowledgment were received from 

 the Royal Library at Munich, the Royal Academies at Pesth 

 and Brussels, and from Mr. S. A. Green, Librarian of the 

 Massachusetts Historical Society. 



A letter was received from Gen. Humphreys, in reply to 



