26 Transactions. — Botany. 



general appearance it approaches S. hicorne, Hauptfleisch (apud 

 Lagerheini in lit. citm icone) ; but that plant has deep quad- 

 rangular crenulations on the edge in front-\'ie\v, which are 

 absent from our species. The zygospore resembles somewhat 

 that of S. sagittariuju, Ndst. (" Alg. of N.Z.," p. 37), but is 

 much smaller and less angular. 



Staurastrum inconspicuum, Nordstedt, forma gracilior. 

 Plate v., fig. 46. 



Frond very minute ; in front-view sub-rectangular, the con- 

 striction represented by concave sides, and the angles pro- 

 duced into short sub-cylindrical processes slightly bent in the 

 middle and obscurely forked at the tip ; two of these processes 

 can be seen in focus at once at each end, and a third is seen 

 either in front or behind, between each pair. End-view con- 

 vexo-triangular, the angles produced in processes alternating 

 with the three processes of the other end, which may be seen 

 between them. Length of the frond in front-view more than 

 twice the diameter at the isthmus. 



Long, ex rad., 11-7 /x; lat., 9 fj.: lat. isthmi. 4-3 yu,; long, 

 rad., 4 fx. 



Otaki. 



This form is more slender than Nordstedt's original plant, 

 and rather smaller; and the specimens which I have observed 

 are triangular in end-view, tlie American and European forms 

 being quadrangular. Probably forms may exist here with 

 either three or four sides. 



Staurastrum furcatum, Ehrenberg. forma '! Plate V., 

 fig. 47. 



I have only one specimen of this plant, and have not seen 

 it in end-view : it is referred therefore here only provisionally 

 to Ehrenberg's species. It is the one which in my paper of. 

 1882 I considered as probably 6'. spinosum of Ealfs, which 

 several authors {c-Cj., Eabenhorst and Wolle) refer to 5. fur- 

 cafuni. The species appears to be very variable : my figure 

 approaches that of Wolle (" Desm. of U.S.," pi. xlviii.), 

 especially in the occurrence of a process or processes on the 

 frond iiear the isthmus. 



Long, ex rad., 26-7 /x; lat., 16-4 fx; long. rad. circ, 5*5 /a. 



Hawke's Bay. 



Staurastrnm brachiatum, Ealfs, var. graciUus, var. nov. 

 Plate v., fig. 48. 



Frond extremely minute ; constriction only a small notch ; 

 segments in front-view sub-quadrate, produced at the outer 

 angles into long, siib-cylindrical, smooth, very transparent 

 processes, which are deeply cut into two or three (mostly 

 three) points; endochrome extending only to the quadrate 



