216 FRESH-WATER ALG^E OF THE UNITED STATES. 



longioribus, extremis obtusis ; polysporis in ramellis lateralibus racemosim et confertira 

 cumulatis, ovalibus vel uonnihil obovatis. 



Diam.Y\\. 5E V/ = -0004". Spor. transv. g^" = .00027 long. 55 V 7 = .0004". 



Syn. G. expansa, WOOD, Prodomus, Proc. Amer. Philos. Soc., 1869. 



Hob. In rivulis, prope Philadelphia. 



Csespitose, forming a dark purple, slippery, indefinite stratum on stones ; filaments purple, 

 moderately branched, almost 2 lines long, together with the branches strict and straight, 

 often elongate ; infertile branches sometimes very few, sometimes very numerous ; fertile 

 branches short, ascending ; joints 3-8 times as long as their diameter, the final articles ob- 

 tusely rounded : polyspores racemose, crowded on the fertile branches, oval or somewhat 

 ovate. 



Remarks. This species was found growing in a running stream, forming a felty 

 slimy coating upon large stones, looking so much like a stratum of Oscillatoria, 

 that when I gathered it I thought it probably was a representative of that genus. 

 The stratum, however, when carefully examined, is seen to be made up of an in- 

 definite number of minute, very closely approximate tufts. The color was a dark 

 dull purple. The plant may possibly be the CTiantransia violacea, of KUTZING, 

 which it resembles in many particulars, but it is nearly twice as long and the fila- 

 ments are considerably thicker. Its habit of growth also seems to be essentially 

 different from that of the European plant, so that I have finally decided to con- 

 sider it a distinct species. The exact locality of its growth is in a thickly-shaded 

 portion of the stream that runs along the North Pennsylvania Railroad, just this 

 side of Chelten Hills. 



Fig. 2, pi. 19, represents a filament magnified 125 diameters; fig. 2 a, a part of 

 a fertile branch magnified 460 diameters. 



C. macrospora, WOOD (sp. nov.). 



C. caespitosa, subpollicaris, olivaceo-grisea vel saturate violaceo-purpurea; filis ramosis et 

 ramis plerumque strictis et rectis, et elongatis ; articulis diametro 3-8 plo longioribus ; ramu- 

 lis fertilibus brevissimis ; polysporis singulis vel geininis, sparsis, saspe distantibus, globosis, 

 interdum nonnihil ovalibus. 



Diam. Fil. plerumque .0008 max. .001. Polysp. .0009. 

 Hob. South Carolina ; (Ravenel). 



Caespitose, about an inch long, olive-gray to deep-violet purple ; filaments a good deal branched, 

 with the branches mostly straight and elongated ; fertile branches very short ; articles 3-8 

 times longer than broad ; spores single or geminate, few, often distant, globose, or sometimes 

 slightly oval. 



Remarks. I am indebted to Prof. Ravenel for specimens of this species pre- 

 served in carbolic-acid water. They are labelled, " Dull olive green, growing 

 against wooden boards in spring, Nov. 5, 1869. Aiken, South Carolina." The 

 most of the mass is of the color noted, or at least approaches it, but a portion is 

 almost blackish purple. The species is a very distinct one, characterized by 

 the larger diameter of its articles and spores, by the paucity and shape of the 

 latter, as well as by its variance in coloration. In some old specimens the cell 

 wall is distinctly lamellate. I have only seen fruit on the purple filaments. The 



