FUKSll-W A TKK A !.<,.!: <>1 Till! I N 1 T I! H STATES. 171 



Fi. Ha, pi. 1"), represents part of a sterile filament of this species; 3 J, portion 

 of u pair of fertile filaments, both magnified TJ") diameters. 



. ra*a, 



Sp. Imte viridis, denique sordido viridis; articulia stcrilibus diametro Rulxequalibus, post divi- 

 Bionem iiitcrduiii fere ^ plo brevioribus, ante diviaioncm ssepo fere 2 plo longioribus; cytio- 

 dcrmatc tfiiui, houinirriic.), utroque fine ncc protcnso nee replicato ; fasciia spiralibus 4, 

 driitutis M! tiilifrriilutis, stepe arctis, snbtransversis, tenuibus ; anfractibns 1}-I; ccllulis 

 fructiferis aliis .similliiiiis, huud iuflatia ; zygosporis globosis vel ellipticis. 



,s'i/;i. Sj>. ,-rii.i.iii, KT/. KABENHORST, Flora Europ. Algarum, Sect III. p. 240. 

 Huh. In stagnis, prope Philadelphia. 



Bright irrrm, but finally a dirty green ; sterile articles about as long as broad, sometimes after 

 division only half as long, sometimes before division twice as long; cytioderm thin, honio- 

 _' ..... ins. nut infnMrd ur produced at the ends; spiral filaments 4, dentate or tuberculate, 

 often close, subtransverse, thin; turns from 1J to 4; fertile cells very like the others, not 

 inflated ; zygospores globose or elliptical. 



/,'- murk*. This species is very common in the neighborhood of this city, occur- 

 ring in springs, &c., but especially in the ditches in the Neck. It forms long, 

 lubricous masses, of a bright green color, readily distinguishable by the size of the 

 filiiiiicnts, which are separated with ease by the unaided eye. I have gathered it 

 repeatedly, in fruit, from the middle of April to the middle of June. In this state 

 the iiia^s lias lost its bright green color, and when the filaments are closely examined, 

 even without a glass, minute dark points mark the positions of the spores. 



l''i.il. -1 ". pi. 15, represents part of a filament commencing reproduction ; 4i, fila- 

 m.'iits which have matured the spores; 4 c, a pair of conjugating filaments. 



Genus ZYGNEMA. 



Ccllulic vcgctativtB cyliudricte. Massa chlorophyllacea initio rfTusa et snbhomogenea, postca dis- 

 tiuctc grauulosa aut per cellulae lumen distributa, granula amylacea duo centralia involrens, ant in 

 ror|i<iribus duobus (in quaque cellula) plus minusve distincte stellatim radiantibua juxta nuclcum 

 cfiitraluiu granum amylaceura unicnm involvcntibus collocata. Conjugatio scalariformia vcl late- 

 ral is. 



-'tative cells cylindrical. Chlorophyl masses in the beginning effused and Kubhomogencona, 

 aftiTwards distinctly granular, either distributed throughout the cavity of the cell, involving two 

 mitral starch granules, or gathered together into two masses (in each cell), with more or less dis- 

 tinctly stellate radii and a central starch granule placed near the nucleus, one on each side of it. 



Z. inwigne, (HASBALL) 



Z. caespitibns ct plernmque natantibus vel in aqua diffusis, saturate viridibus vel ssepe sordide 

 fiavo-viridibus ; articulis sterilibus diametro circiter Kqnalibns vel duplo longioribus ; conju- 

 gatione scalariforme (et ssepe simul lateral!, R.); zygosporis globosis; sporodermate l;evi. 



Diam. Cell. ^ n " = .00126"; spor. Ts'oV' rAW - 0.00093" 6.00016". 

 S>jn. Tyndaridva insignia, HASSALL, Fresh-Water Algte, vol. i. p. 163. 



Zygnema insiyne, ( II ASSAM.) KUTZINO. RABENHOBST, Flora Enrop. Algte, Sect. III. 

 p. 249. 



Bab. In stagnis, prope Philadelphia ; Wood. Rhode Island; (S. T. Olncy) Thwaitea, 



