138 



FRESH-WATER ALG.E OF THE UNITED STATES. 



1m-'. ri, 1)1. 21, rrprescnts tlio front view oi' an empty half frond of this species, 

 raasnificd'iJO diameters; fig. 12 a, the side view of au empty frond. 



E. alliiii', Kalfs. 



E. E. liumcTosum affine, paulo minus ; semicellulae quinquelobae ; lobi basales quales in E. hume- 

 rosum scd tumores quataor iu serieui trausversam siinplicuin dispositi, lulii iiiterniedii valde 

 abbreviati eoi-umquc basi tumoribus duobus instructi, lobus polaris magis porrectus et in 

 apice minus dilatatus; cytiodema subtilissime punctatum sublaive. (R.) 



Long. 0.003S"— 0.U041". (K.) 



Syn.—E. offiiic, IIalfs, British Desmidecc, p. 82. 



Bah. — South Carolina; Georgia; Bailey. 



Frond aljout twice as long as broad; segments 3-lobed ; basal lobes slightly eraarginate, 

 havin"'- intermediate between tliem and tlie end lobe on caeli side a tubercle representing 

 middle lobes, the upper margin of wliieb is horizontal ; end lobe exsertcd, dilated, its notch 

 linear. 



Emiity frond ; f v. minutely punctate ; the segments with four basal inflations, two above and 

 two on end lobe ; tr. v. elli])tic, with four inflations on each side and one at each end; e. v. 

 end lobe emargiuate at opposite ; e. v. end lobe emarginate at opposite external margins, 

 producing four shallow lobulets. (A.) 



E.Didelta, (Turpin) Ralfs. 



E. robustum, diametro duplo longius etiara supra, in sectione transversa ellipticam, ambitu un- 



dulato-crenatum, in utroijue latere crenis quaternis ; seraicellulis pyramidal ibus, quinqueluhis, 

 tumoribus 9 in series tres alternantibua oi'dinatis, lobis inferioribus oblique truncato-rotundatis 

 nonnunquam leuiter retusis, intermcdiis subadscendentibus, rotundatis, lodo polari minus 

 dilatato, bifido, scgmentis rotundato-truncatis, eoniiiventibus, in apiee tumidis ; cytiodermate 

 distincte jtunctato, punctis modo irregulariler sparsis modo io scriebus reclis collocatis. (K.) 



Long. O.OO.'JS". Lat. 0.00279". 



Syn. — E.Didelta, (Turpin) Ralfs, British Desmideae, p. 84. 



Hah. — South Carolina ; Georgia ; Rhode Island ; Bailey. Pennsylvania; Wood. 



Frond rather more than twice as long as broad; segments pyramidal, inflated at the base and 



again at the middle, cud scarcely dilated, rounded, its notch linear. 

 Empty frond punctate ; f v. segments with several inflations in lines and two at the end ; tr. v. 



elliptic with four inflations at each side and one at each end ; e. v. end lobe entire at margin. 



Sporangium orbicular, with subulate spines. (A.) 



Eemarh. — Fig. 13, pi. 21, represents this species. 



E. ainiiiillac'cuiii, Ralfs. 



E. diametro duplo longius ; seraicellulis trilobis, ad basin tumidis, e basi lati.ssiraa subito in lobi 

 polaris collum attenuatiS; !o!)is liasalilnis maximis integris, loco loborum intermedioniiu pro- 

 cessu deutiformi, lobo polari cuncato, in apice bifido, segmentis late truncato-rotuudatis; 

 cytiodermate subtiliter punctate. (R.) 



Long. 0.0035"— 0.0038". Lat. max. .0026"; lat. in colli (lobi polar.) 0.00085". (R.) 



Syn. — E. ampuUacciim, Ralfs, British Desmideae, p. 83. 



Eab. — South Carolina ; Florida ; Bailey. 



Frond rather more than one-half longer than broad ; segments obscurely 3-lobed, short, with 

 broad inflated base ; basal lobes not emarginate, having on each upper side a small inter- 

 mediate tubercle between each and the end lobe ; cud lube exserted and dilated, its notch 



