50 Allan Hancock Pacific Expeditions vol. 26 



38. Internodes, except near tips, 4-10 times as long as cortical 



band; nodes of only 2 tiers of cells C. affine S. & G. 



(Japanese plants treated by Tokida as C. cimbricum 



Peters, are very similar and perhaps not distinct, but the 



type of that little-know European species was sterile.) 



39. Lower internodes 2-6 diameters long; nodes often with 



whorled rhizoids C. tenuissimum J. Ag.? (Japan) 



39. Lower internodes mostly less than 2 diameters long; without 



whorls of rhizoids at the nodes 40 



40. Lower cells of cortical band producing descending 



rhizoidal appendanges lying along axial cell wall 



C. personatum S. & G. (in part) 



40. Not as above 41 



41. Cortical band consisting of larger, rounded, downwardly 

 directed cells in lower part of band, and smaller, angular cells 

 in upper part; lower internodes 1.5-2.0 times as long as 



broad; branching distant C. caudatum S. & G. (in part) 



41. Cortical bands with irregularly arranged, small, angular cells 

 on the surface throughout; lower internodes mostly less than 



as long as broad; branching rather dense above 



C. zacae S. & G. (in part) 



42. Upper branches reduced in diameter, commonly 100 /a or 

 less ; tetrasporangia appearing large compared to bearing 

 cortical band, 1/4 the diameter of the band or larger .... 43 

 42. Upper branches not much reduced in diameter, com- 

 monly over 150 p. (to 300 ti) ; tetrasporangia mostly 



appearing small compared to bearing cortical band 44 



43. Older internodes less than as long as broad 



C. zacae S. & G. (in part) 



43. Older internodes 1.5-2.5 times as long as broad 



C. caudatum S. & G. (in part) 



44. Apices prominently circinate-forcipate; tetrasporangia 

 mainly projecting from adaxial surface of the node or 



sometimes scattered around the entire node 



C. clarionense S. & G. 



44. Apices not circinate; tetrasporangia whorled, projecting 

 from upper half, particularly the upper margin, of the 

 cortical band C. ornatum S. & G. 



Ceramium affine Setch. & Gard. var. affine 



PI. 17, fig. 6 



Setchell & Gardner 1930, p. 172; Dawson 1944, p. 317, pi. 51. fig. 4; Dawson 

 1950, p. 132. 



Thalli 8- 12 mm high, epiphytic or entangled, 30-40 tt in diam, at the 



