54 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



Ghaetomorpha Linum (Miiller) Kiitzing 



Filaments entangled, rather soft, to 300 /x diam., the cells 1.7-3.0 

 diameters long, with rather thin walls, slightly contracted at the septa; 

 not adhering well to the mounting paper. 



Taylor 1928, p. 60, pi. 4, fig. 11 ; 1937, p. 80, pi. 1, figs. 1,2; 1942, 

 p. 23. 



This material consists of a much softer plant than C. Linum as en- 

 countered in New England. However, it resembles very closely material 

 from Tunisia (collected by Schussnig 1924, determined by Schiifner as 

 f. mollis), and some of the West Indian material, in the writer's herba- 

 rium. 



Ecuador: Archipielago de Colon, scarce, entangled among Sargassa 

 as driftweed, I. Wenman, no. 34-82, 11 Jan. 1934. 



RHIZOGLONIUM Kiitzing, 1843 



Plants filamentous, the filaments uniseriate, the cells with few to 

 several nuclei and much-dissected chromatophores with small pyrenoids; 

 branching absent, or if present the branches short and rhizoidal, or rudi- 

 mentary few-celled spur branches. 



KEY TO SPECIES 



1. Rhizoids absent 4 



1. Rhizoids present 2 



2. Filaments not over 50 /x diameter 3 



2. Filaments generally over 50 ju. diameter . . . . R. rhizophilum 



3. Mass slippeiy ; filaments 35-40 jx diam. ; rhizoidal branches short, 

 rare R. lubricum 



3. Mass soft; filaments 10-35 [i diam.; rhizoidal branches relatively 



frequent R. riparium 



3a. Branches few, short and continuous with the originating 



cell, or apparently wanting v. implexum 



4. Filaments 55-75 jii diam., walls 5-11 /x thick 



R. crassipellitum v. robustum 



4. Filaments 10-14 /* diam.; cells to 3-7 diameters long . R. Kerneri 



Rhizocloniuin crassipellitum W. & G. S. West, v. robustum 



G. S. West 



Plants forming tangled masses; filaments of irregular contour, 55-75 

 fi diam., the cells 1-2, rarely to 3 diameters long; cell walls 5-11 /t thick; 

 rhizoids absent. 



