102 WISCONSIN PHYTOPLANETON 



that end in three divergent spines of medium size, upper and lower 

 margins of processes deeply creniilate, processes parallel to somewhat 

 convergent; median area of apex of cell body with a transverse sub- 

 apical row of 8-10 emarginate verrucae. Vertical view elliptic, with 

 a row of 8-10 emarginate verrucae just within each lateral margin; 

 poles of cells continued in long tapering processes that have the same 

 appearance as in the front view. (Tychoplanktont.) 



Zygospores unlcnown. 



Cells 68 fx long; breadth with processes 143-162 /i,, without proc- 

 esses 45-58 /i; breadth at isthmus 13.5 /x; thickness 24 /a. 



Des Moines (rrr), Fish (rrr), Owen (rrr). 



The largest of the biradiate members of the genus and one with 

 a distinctive shape of the semicells and subapical ornamentation. 



40. Staurastrum leptocladum Nordstedt. PI. 78, Figs. 1-7, 



Vidensk. Medd. f. d. naturhist Foren. i Kiobenhavn 1869: 228, pi. 4, fig. 57. 

 1870; W. & G. S. West, Jour. Linn. Soc. Bot. 33: 317. 1898. 



Staurastrum leptocla-dum var. cornutum Wille, Bih. Sv. Vet.-Ak. Handl. 8, 

 No. 18: 19, pi. 1, fig. 39. 1884; Johnson, Bull. Torr. Bot. CI. 21: 289, pi. 211, 

 fig. 3. 1894; W. & G. S. West, Trans. Linn. Soc. 2nd. Ser. Bot. 5: 79, pi. 9, 

 figs. 12-13. 1895. 



Cells fairly large, breadth (without processes) about half the 

 length, slightly constricted, sinus a small semicircular depression, 

 isthmus relatively broad ; semicells subcampanulate, with bases in- 

 flated and apex strongly tumid ; angles continued in long slightly 

 attenuated processes that are at first outwardly divergent and then 

 curve gracefully away from the isthmus, upper and lower margins 

 of processes finely crenulate and ends bispinate ; basal inflation of 

 body of the semicells usually with a single transverse row of conical 

 or vertically elongate granules, rarely smooth, median portion of 

 semicell body with a tumid protuberance and dorsal margin with a 

 single vertical subapical spine. Vertical view narrowly elliptic, with 

 poles continued in straight slightly tapering processes with undulate 

 margins, ends with two small spines that lie in the same vertical 

 plane; median part of lateral margin slightly truncate. (Faculta- 

 tive planktont.) 



Zygospores unknown. 



Cells 71-95 fx long with processes, 35-41 ju, long without processes ; 

 breadth with processes 67-105 ix, without processes 18-21 /x ; breadth 

 at isthmus 6-7 /a ; thickness 10-12 /x. 



Bear (sss). Bone (r), Carrol (s). Chain (sss), Clare (ss). Cranberry (rrr). 

 Deer (s). Devils (r). Diamond (s). Grindstone (rrr), Half Moon (rrr), Horse- 

 shoe (c), Jag (rr), Little Butternut (rrr). Loveless (rr), Nancy (rrr), Sand (rrr), 

 Sishebogema (rr). Trapper (sss), Whitney (rr). 



The species and its varieties are distinguished by the curvature of 

 the processes, at first divergent and then upwardly curved. Nord- 

 stedt in his description does not mention the subapical spine, a fea- 



