170 1' RES II -WATER ALG.E OF THE UNITED STATES. 



. Diam.— 0.0025". 



Si/n.—S. nilida, (Dillwyn) Link. Rabenuoust, Flora Europ. Algarum, Sect. III. p. 245. 



/7„6._Prope Philadeli>bia. 



Occum'ns?- in lubricous turfy masses, of a deep green color; sterile joints after division about 

 a.s long as broad, before divisiou 2-3 times longer ; fertile joints similar to the others, nut 

 tumid; spiral filaments 4, moderately broad, turns 1-2; zygospores elliptic. 



Remarl-s. — This species appears to be somewhat rare, at least I have found it 

 but once, and tlicn only in small quantity. Rabenhorst states that there are occa- 

 sionally only three spirals, and his maximum diameter is 0.0031"; he also speaks 

 of the fertile johits as "vix tumidis." 



Sp. diliila, Wood. 



Sp. articulis sterilibus dianictro subaHpialibus ad duplo longioribus, frnctiferis baud tnmidis; 

 fasciis spiralibus 5, angustissimis, laxis, valde nodosis ; anfractibus plerumque i, interduin 

 1 ; zvgosporis sparsis, late ellipticis vol ovatis aut globosis; cytiodermate modice teuue, in 

 utroque fine uec protcnso nee replicato. 



Biam.—Avtic. steril. j^^" = .003". 



Sijn.—S. diluta, Wood, Prodroraus, Proc. Am. Philos. Soc. 18G9, p. 139.] 



Edb. — In stagnis, prope Philadelphia. 



Sterile joints about as long as broad to twice longer, fertile cells not swollen ; chlorophyl kands 

 5, exceedingly narrow, lax, strongly nodose ; turns mostly ^, sometimes 1 ; zygospores few, 

 broadly cllijitical, ovate or globose ; cell wall moderately thin, not infolded at the cuds. 



BemarJcs. — I have found this species several successive seasons growing in the 

 ditches in the Neck, below the city, especially in the neighborhood of the large 

 stone barn, built by the great millionaire, and still known as " Girard's Barn." 

 The spirals are very narrow and slender, and are moderately close to one another. 

 They arc chiefly made up of a number of chlorophyl nodules, the connecting thread 

 between which is often very faint. In all the fruiting specimens, as I have seen 

 them, the spores have been very few in number, most of the ccUs of the fertile 

 filaments appearing to have aborted, so that they are simply empty. In most cases 

 only about every third or fourth cell contained a spore. 



Fig. 2, ul. 15, represents this species. 



Sp. setiforniis, (Roth) Ktz. 



Sp. saturate viridis, lubriea ; articulis sterilibus diametro paullum brevioribus ad 1^ plo lon- 

 gioribus ; articulis fructiferis hand inflatis ; fasciis 3-8, latis, dentatis, interdum nonnihil 

 remotis, sed soepe arete et dense conjunctis, nodosis ; zygosporis globosis vel late ovalibus. 



Diam. — .0035". 



Syn. — S. setiformis, (Roth) Kxttzino. Rabenhorst, Flora Europ. Algarum, Sect. III. p. 246. 



Hah. — In stagnis, prope Philadelphia. 



Deep green, slippery ; sterile joints a little shorter to one and a-half times longer than broad; 

 fertile joints not inflated ; spiral filaments 3-8, broad, dentate, sometimes somewhat remote, 

 sometimes closely and densely conjoined, nodose ; zygospores globose or broadly oval. 



Rcmarhft.—^oriG of the descriptions which I have seen of this species state the 

 number of the spiral filaments, but the other characters of the American form sc 

 agree with those of the European plant that it is probable that this one does also, 

 The jjlant is not uncommon in the Neck, fruiting in the spring. 



