FRESH -WATER ALG^ OF THE UNITED STATES. 199 



0. gynandrous, very elongate ; joints 6-14 times longer than broad ; sporangia globose, mostly 

 depressed, about .0014" in diameter; oospores of the same form as sporangia, whose cavity 

 they almost fill ; covered with sharp spines ; the lateral pore placed above the middle ; aa- 

 theridia bicellular ? 



Bern arks. — I found this distinct species in a little stagnant pool in the 

 wilderness, known as Bear Meadows, in Centre County, of this State. The fila- 

 ments are very long, and were matted together into a sort of fibrous mass. The 

 male plants were few in number, and were attached to the female plant in the 

 neighborhood of the sporangia. I have not seen any composed of more than two 

 cells. They are furnished with a well-marked foot, above which there is a short 

 neck. As I have seen them they are nearly straight. 



I have not been able to make out more than one coat to the spores. This coat 

 is very thick, and is furnished with numerous thorn-like spines. These are very 

 sharp at the points, but at their bases are mostly very robust. 



Fig. 3, pi. 18, represents a spore of this plant magnified 750 diameters. 



Subfamily BULBOCHtETE^. 



Filuma ramosum, setis strictis hyalinis achrois e basi bulbosa et plus minus elongatis instructum. 

 Filaments branching, furnished with straight, hyaline, more or less elongated seta, arising from a 

 bulbous base. 



Remarhs. — The Bulbochcetece are at once separated from their allies the CEdogo- 

 niecB by their bushy, branched habit of growth. The shape of the individual 

 cell is also entirely different, for instead of being regularly cylindrical they are 

 almost always markedly dilated at their distal end, so as to be somewhat clavate, 

 nor is the filament or its branches ever ended by a long seta-like series of narrow 

 colorless cells. Many or all of the cells are, however, furnished with a single 

 very long unicellular unbranched hair. These hairs are colorless, hyaline, and 

 provided with a markedly and abruptly bulbous base. The BuTbochcetece grow in 

 similar positions to their allies, but are not nearly so common, nor when present 

 do they grow in such abundance, very rarely, if ever, forming the dense forest-like 

 fringes or the matted masses that some species of the CEdogoniece do. They are 

 reproduced both by zoospores and resting spores. 



The manner of the development of and growth of the plant from the zoospore 

 is very peculiar, I have never myself studied it, but Prof Pringsheim gives the 

 following account: When the zoospore first settles down it produces a cell closely 

 resembling that of an CEdogonium. The first change which occurs in this cell is 

 the formation of a small, conical, transparent, colorless space at the apex, which 

 space in a little while becomes separated from the mother-cell by a distinct par- 

 tition-wall, and at the same time the apex itself is ruptured, and the point of the 

 little growing cone pushed through the opening. This rupture does not take 

 place irregularly, but by a sort of circumscribed dertiscence, similar to that of the 

 CEdogonium, the top of the mother-cell being lifted up like a little trap-door, and 

 finally pushed aside as the new conical cell grows elongate and becomes converted 

 into a hair. After the formation of this apical hair, the mother-cell undergoes 

 division in a manner similar to that of an CEdogonium. Near its distal end a 



