FRESII-WATEll ALG.fi OF T II E UNITED STATES. 43 



ZHam. Artie. "" - .00016" ; por. T J t ," TI t,," .00026" .00033". 

 Syn. S. Carmichfln, HARVEY, I'livo.!. Brittaniea, T. cxiii. 



> l<.ty*lrma, (Krz ) KAMkNUoWiT, Flora Eurup. Algmrum, Sect II. p. 192. 

 Bab. In stagnis, New .Jersey. 



8. filaments mostly subsolitary, lint ~"im time* associated and interwoven together, light bluish- 

 green, slraighti&h, or variously curred and flexuoug ; articles cither ttubitpberical or shortly 

 cyliiulrii-ul ; hetrrocysls globose or very broadly elliptic, a little larger to twice aa large in 

 diameter as the ordinary joints ; i-|M.r. s nmrc or less elongate, cylindrical, in the uncertain 

 condition sparsely granulate, lijrlii blui.-h-frrem, with the incnibrauc not distinct, in the 

 mature state densely granulate, and with a tliicLi.ili membrane. 



Remarks. I found this species growing in a brownish jelly, with various other 

 algo>, in a pool east of Caniden, New .In -. y. The filaments were mostly scattered, 

 but in some places numbers of them were collected in little masses. In some fila- 

 ments almost all the cells were developed into spores, so that a single thread con- 

 tained ten or even more spores. In by far the larger number of such cases there 

 was bi'twfi-ii each pair of spores a heterocyst; sometimes, however, the latter waa 

 want in.-,', and the spores would be attached to one another. 



My sjM-cinicns differ somewhat from the European form, but are too close to 

 sc]),iratc from them. They equally resemble, however, S. Carmiduflii. Indeed, I 

 cannot see any sufficient reason for separating the species. S. Carmidtcelii is, to 

 be sure, a salt-water plant. I have, however, received specimens collected by Dr. 

 Lewis, near Stonington, which I believe grew in salt water, and which agree in 

 : \ ropn-t with my fresh-water specimens. 



Fig. 3, pi. 3, represents a portion of a filament, magnified 750 diameters. 



FAMILY RIVULARIACK/E. 



Thallus gclatinosns, mollis vel induratus, vel crustaceus, interdum calce impletus, subglobosus 

 vel amorphus. Trichomata ad oscillarium morem articulata, vaginata, Bed interdum state protect* 

 cum vaginis in gelatinam matricalera confluentibns et baud visibilibns, simplicia vel pseudoramosa, 

 superne attenuata, sepius in apicem piliformem longe producta, parallel* vel radiatim dispoaita, 

 cellula basale hyalina globosa et interdum ccllulis interstialibus instruct*. Sporae (manulria, KTZ. ), 

 eingulc plcruinque inter cellularo perdurantem basilarem et cellulas vcgetativaa positac, sajpe per- 

 magnae, cylindricte, plernmque pachydermaticae. 



Vegetatio terminalis. Propogatio sporis tranqnillis. 



Thallus gelatinous, soft, or indurated, or crnstaooons, sometimes filled with lime, subglobose or 

 amorphous. Trichomata. articulated like an oscillatoria, vaginate, but sometimes, when old, with 

 the sheaths confluent in the maternal jelly and not visible, simple or pseudoramose, attenuated 

 above, often with the *pez prolonged into * long hair, parallel or radiately disposed, furnished with 

 globose hyaline, thick-walled basal cells, and sometimes with interstitial cells. Spores cylindrical, 

 generally placed between the basal and vegetative cells, often very large, mostly with thick coaU. 



Vegetation tranquil. Propagation by means of tranquil spores. 



Remarks. In the Rirulariacfrv the thallus is always small ; but is most gene- 

 rally in the various species somewhat definite in form and size. Its consistency in 

 our North American forms varies from that of an exceedingly soft, formless jelly 

 to that of a gristly mass. The maternal jelly is usually colorless, sometimes brown- 

 ish or yellowish. There is never any condensation of the outer portion of the 



