FKESII-WATEIl A L Q .E OF T II K U N I T E D ST A T E 8. 39 



lulls pcrdurantibus interjcctis, articulis vcgctativis Bubequalibus, utroqoe polo pnnctifonne 

 incra.ssutis, subsphiLTicis; uporis aubsphieriris. 



Syn. A. jfjantra, WOOD, Prodrouiug, Proc. Amcr. .Philos. Soc., 1869, 145. 



Hub. In staguis uatautc, prope l'hiliulfl|>hiu. 



Diam. Artie, vegetal. max. j^,,. lleterocysts , .0005. Spor. lat iJJn <- Long. 



Thallus wanting ; filaments occurring floating singly on water or in great ntmibera, straight, 

 but in the young state often spirally con volute ; urtirlf* mostly subglubuse, closely connected, 

 granulur, lirterix-ysU Rutophcrirul, interstitial, a very little larger than the vegetative cells, 

 thirkriietl at each end in a punetifunu manner; spore subspherical. 



// mark*. This plant was found by myself, late in the summer, floating upon a 

 l>rick-|>nud l>elo\v tin- city, forming a part of a thick, dirty-green, "pea-soup 

 colored," almost pulverulent scum. The filaments, though occasionally in great 

 numlx T-, \\ere never, that I saw, joined together by any jelly so as to form a frond. 



1 u' ">, pi. 3, represents a short filament of this species magnified 750 diameters. 



Genus CYLINDROSPERMUM, KTZ. 



Spore ante cellulam tcrminalem ortas. 



Spore developing from the next to the terminal cell. 



('. minutiira, WOOD. 



C. trichomatibus dilute irrugincis, plerumque flexuoso-cnrratis et intricatis, intcrdum subrectis ; 

 art iriilis ry limit-ids, ad genicula plus minus constrictia, bomogeneis vel grannlatis; cellulis 

 perdurantibus terminalibus, hireutis, globosis; gporis ellipticis, diametro 2 3 plo longioribus, 

 subtili.ssime granulatis. 



Syn. C. minutum, WOOD, Prodromus, Proc. Araer. Philos. Soc., 1869, 126. 

 Diam. Artie. ,aW; 8 P r - long- rAa"; transv. ,^,,". 

 Hub. In stagnis prope Philadelphia. 



Filaments light ternginous-green, generally curred and intricate, sometimes straightish ; article* 

 cylindrical, more or less constricted at the joints, homogeneous or granulate ; heterocysts 

 terminal, hirsute, globose; spores elliptical, 2 3 times longer than broad, very minutely 

 granulate. 



Remarks. This species was found by myself at Spring Garden, New Jersey. 

 "W ith a number of other alga? it formed a ferruginous-brown gelatinous mass, 

 growing in a deep, shaded, very stagnant pool. In most instances the filaments 

 were closely interwoven, and sometimes formed minute greenish balls, just large 

 enough to be visible to the unassisted eye. In other instances they were mixed 

 up with various algae in little indefinite masses. There is apparently a stage in 

 the life of the plant, when it consists of a single filament enclosed in a little cap- 

 sule, for mixed in with the rest of the gelatinous scum were little microscopic, sub- 

 globose masses, with a firm outer periderm and a single filament coiled up in the 

 centre. The color of the filaments was generally a faint bluish-green, sometimes, 

 however, with a yellowish tint. The spores were decidedly yellowish. 



Fig. 6, pi. 2, represents a fragment of a filament with the spore magnified 800 

 diameters. 



