THE MARINE BOTANIST. 181 



narrow, and the ciHa much drawn out, cylindrical 

 and branched. Several fronds arise from the 

 fibrous root. Annual. Fruits in summer, while 

 JR. cUiata produces its fruit in winter. Grows on 

 rocky or gravelly shores in tide pools. Frequent. 



RHODYMENIA PALMATA.— HAND- 

 SHAPED RHODYMENIA. 



Fronds from two to twenty inches long, broadly 

 wedge-shaped, divided in a palmate manner, or nar- 

 row and forked, in some forms cleft into very narrow 

 finely-divided segments. Tetraspores in cloud-like 

 spots, spread over the whole surface of the frond. 

 Substance tender when young, but afterwards thick 

 and leathery. The following well-marked varieties 

 are enumerated in the Phycologia Britannica : — 

 p marginifera ; frond oblong, sub-simple, prolife- 

 rous at the margin, y Simplex; fi:'ond undivided, 

 wedge-shaped. These two forms grow on the stems 

 of Zr. digitata, S Sarniensis ; frond laciniated, 

 the segments narrow and sub-linear, e sobolifera ; 



