FUKSH-W ATKK A L ^E OF TUB UNITED STATES. H7 



Syn. J/. Jrnnen. K.M.r.-. J'.ritish PeMiiidiea', p. 16. 



Hah. prope Philadelphia; Wood, Suitli Carolina; (IlaTcnel) 



Large, oblong, Tor the must part finely granulate ; semicells 5-lobod ; lobes wedge-shaped ; banal 

 and inti-rinvdiatc, about equally broad ; end lobe broadly truncate or broadly rounded, iu the 

 middle Minn-times slightly aud obtusely eniarginate, sometimes rather deeply emargiiiate. 



/,'. mark*. I have found this species near Philadelphia, and also received it from 

 Prof. Kavenel, 1>\ whom it was collected in South Carolina. The American plant 

 ditl'ers from the typical form in not having the ultimate lobules emarginate, they 

 bring merely a little hollowed out in the centre, and sometimes scarcely this. The 

 angles in >oine specimens are also more acute. Mr. Archer, however, speaks of a 

 variety occurring in England, in which these lobules are not emarginate, and I do 

 not think characters can be found separating the American from the European 

 forms. The median suture is in all the specimens very narrow and deep, a were 

 line, as it were, -extending nearly to the centre. 



;. 7, pi. 13, represents a frond of this species. 



M. Torreyi, BAII.ET. 



M. pcrmagna, oblongo-orbicularis, laevis, proftindissimc lobata; semicellnlis quinqnelobis, lobU 

 basalilms profunde bifidis, laciniis inferioribns apicc bidentatis, superioribns integris, lobis in- 

 termediis profunde trifidis, laciniis supcrioribns bidentatis, inferioribus integris, lac. omnibus 

 lanceolatis acuminatis, inferioribus paulum incnrvis, superioribus rccurvia ; lobo polar! non 

 prominente, e basi angusta seusiiu dilatato, in vertice acute siuuato, ougulis iutegris acumin- 

 atis. (R.) Species mihi ignota. 



fyn. M. Torrryi, BAILEY. KAI.KS, Brit. Desmidieae, p. 210. 



J/ufi. Prope Princetown, New Jersey; Bailey. 



Frond smooth ; segments 5-lohed ; basal lobes bifid, middle lobes trifld, the subdivisions nearest 

 the opposite segments and those nearest the terminal lobe bidentate at the apex ; the inter- 

 mediate three terminating in acute points; all somewhat inflated and tapering ; terminal 

 lobe narrow, not exsertcd, spreading at the angles into divergent tapering points, ends 

 slightly cmarginate. (A.) 



HI. foliacea, BAILET. 



M. parva, subquadrata, Isevis; semicellnlis trilobis, lobis lateral ibus profunde bifidis (undc rec- 

 tior semicell. quinqnelobse), lobulis inaequaliter inciso-dentutis, loldilis inferioribua rectis, 

 superioribus recurvis; lobo polar! plus minus prominente, anguate cuneato, in vertice plus 

 minusve emarginato, angulis aut acutis iutegris aut productis, bidentatis. U. Species mihi 

 ignota. 



Syn. M.foliacea, BAILEY. RALFS, British Pcsmidieae, p. 210. 



///,._" AVorden's Pond, Rhode Island; Bailey." 



Frond subquadratc, smooth ; segments 3-lobcd ; lateral lobca deeply bipartite, inciso-dcntate, 

 their margins concave, inciso-serrate; end lobe brond, cuneate, and exserted, bipartite at the 

 angles, the subdivisions narrow, and minutely dentate at the extremities ; end concave. (A.) 



Genus STAURASTRUM, METEN. 



Cellulse libere natantes, in medio plus minns profunde constricts? ; seraiccllula! a vertiee 3-6 angn- 

 larcs vel radiate. Cytioderma aut leeve aut puuctatum aut verrucosum out aculoatum, nonnunqnam 

 ciliis vel pilis obsessnm. 



Cells swimming free, more or lees profoundly constricted in the middle; semieells when seen 

 from the vertex 3 to 6 angular or radiate. Cytioderm either smooth or punctate, or vcrruoosu or 

 aculeate, sometimes covered with baira or cilia. 



