NO. 1 DAWSON: MARINE RED ALGAE OF PACIFIC MEXICO 47 



10. Branching sparse; nodes not evident 



C. hoivellii S. & G. 



10. Branching more or less abundant; nodes evident 11 



11. Apices more or less incurved; with many proliferous branches, 



but these not congested in upper parts 



C. pacificum (Collins) Kylin (in part) 



(Note that C. kondoi Yendo em. Nakam. keys out here and is 

 distinct from both C. pacificum and C. rubrum (Huds.) Ag.) 



11. Apices straight 12 



12. Plants 15-25 mm. high; apices divergent; with many 



short proliferous branches densely congested above 



C. viscainoense Daws. 



12. Plants 2.5-10 cm. high; apices not particularly divergent; 



branches not especially congested above 



C. japonicum Okam. 



13. Cortical bands only slightly separated above, covering the 

 expanding internodes below by basipetal growth, but the 

 secondary cortication thin, loose, often incomplete; with many 



proliferous branchlets C. washingtoniense Kylin 



(C. hoodii Taylor keys out here and is remarkably similar to 

 C. washingtoniense despite wide geographic separation) 



13. Nodal cortication discontinuous, particularly so in lower parts, 

 usually continuous above or irregularly discontinuous ; usually 



with conspicuous proliferous branchlets 



C. sinicola S. & G. 



14. Plants bearing conspicuous multicellular spines 15 



14. Plants without conspicuous spines 16 



15. Spines mainly abaxial, more or less deciduous 



C. paniculatum Okam. 



15. Spines whorled at the nodes, persistent 



C. hamatispinum Daws. 



16. Cortical bands showing conspicuous basipetal and (or) 



acropetal secondary growth 17 



16. Cortical bands without conspicuous basipetal or acropetal 



secondary growth 18 



(But see C. personatum which has in part basipetal 

 rhizoidal cells.) 



17. Tetrasporangia immersed within the cortical band 



C. evermannii S. & G. 



17. Tetrasporangia projecting from the cortical band 



C. calijornicum J. Ag. 



