52 FRESH-WATER ALGJ3 OF THE UNITED STATES. 



Remarks. I found this plant in a stagnant pool in " Bear Meadows," forming a 

 filamentous, felty mass with (Kloyonium eclunatum and other algae. The variously 

 curved and interlaced flexible filaments are always simple and of uniform, or 

 nearly uniform, diameter through their whole length ; excepting that in some 

 instances there are small, local, bulbous enlargements of the sheath. Though the 

 ends of the filaments in all the specimens I have seen are abruptly truncate, it is 

 very possible that in the young trichoma the apex is prolonged into a long hair as 

 in most of the Mastigonema. The inner filament is sometimes very distinctly arti- 

 culated, often, however, it is not at all so. The sheaths are firm, not at all lamel- 

 late, and generally project beyond the inner trichoma. The spores are cylindrical, 

 yellowish, with a pretty distinct, although very close coat. They are always in- 

 closed in distinct cells, and are mostly several in a filament, placed at intervals in 

 its length. 



This is the first instance, at least that I know of, in which a species of this 

 genus has been found in fruit, and it is interesting to note the resemblance of the 

 spores to those of the more commonly fruiting rivularias. At the same time the 

 peculiar arrangement of the spores is remarkable, and if the other species of Mas- 

 tigonema should be found to have the more common exclusively basal arrangement 

 of spores, I think it would afford good ground for considering M. fertile as the type 

 of a new genus. Moreover, the filaments are not united into a distinct thallus, and 

 also wantthe apical hair of Mastiyothrix, so that it is very probable that they represent 

 an undescribed genus-. Until, however, the fructification of the European species 

 is elucidated, it seems best to forbear multiplying names. 



Fig. 1, pi. 4, represents a single filament of this species. 



OT. ha I os, WOOD, (sp. nov.) 



M. caespitulis ; trichomatibus simplicibus, in setate matura valdc elongatis et cum vaginis trun- 

 catis et apertis, in setate imnjatura modice brevibus et in setam modice longam acuroam 

 productis; trichomatibus internis breve articulatis, subtiliter grauulatis continuis vel varie 

 interrupts ; vagiuis firmis, modice crassis, saepe distincte lamellosis, coloris expertibus ; cel- 

 lulis perdurantibus subglobosier 



Diam. Sine vag.= .0003" ; cum vag.= .0005". 

 Hob. In ffistuario, Stonington, Conn. (Dr. F. Lewis.) 



In little tufts; filaments simple, in mature state greatly elongate, and with the sheath truncate 

 and open, in the young condition shorter and often ending in a rather short seta; internal 

 filament shortly articulate, minutely granular, continuous or variously interrupted ; sheath 

 firm, rather thick, often distinctly lamellated, colorless ; heterocysts subglobose. 



Remarks. This species is an inhabitant of salt, or at least brackish water, having 

 been collected in Stonington Inlet by Dr. Frank Lewis. The filaments are very 

 long and always simple ; forming apparent exceptions to this, I have seen once or 

 twice a number of young filaments so united as to give the appearance of having 

 been produced from one old one, and in other cases young filaments growing from 

 the side of an old one ; but I believe those are always set free so soon as they 

 attain a certain size. In one instance there were large, globular cells, with very 

 thick walls, produced, and lying free, in the sheath. Are these spores 1 They are 



