NO. 1 DAWSON: MARINE RED ALGAE OF PACIFIC MEXICO 49 



28. Branching dichotomous C. nakamurai Daws. 



28. Branching irregular, not dichotomous 



C. vagabunde Daws. 



29. Tetrasporangial axes non-forcipate, usually terminally swollen 



C. equisetoides Daws. 



29. Tetrasporangial axes forcipate, the swollen portion well below 



the tips C. templetonii S. & G. 



30. Tetrasporangia naked 37 



30. Tetrasporangia involucrate, at least by bracteate 



filaments 31 



31. Filaments less than 70 /x in diam 32 



31. Filaments 70-200 fx in diam 34 



32. Tetrasporangia solitary at the nodes, the involucres 



unilateral 33 



32. Tetrasporangia whorled at the nodes, the involucres 



symmetrical C. camouii Daws 



33. Tetrasporangia 40-80 fx diam.; filaments 40-70 [x diam.; 



cavity of axial cells terminally acute, basally truncate 



C. mucronatum Segi 



33. Tetrasporangia 20-40 fx diam.; filaments 30-40 fi diam.; axial 



cells symmetrically elliptical C. serpens S. & G. 



34. Lower internodes 5-10 diameters long 



C. tenerrimum (Mart.) Okam. 



34. Lower internodes mostly 2 diameters long 35 



35. Cortical band 1/3 to 1/2 as long as broad; tetrasporangia 

 secund, abaxial, sometimes later whorled, conspicuously involu- 

 crate throughout; without rhizoidal appendages lying against 



the axial cells C. mazatlanense Daws. 



35. Cortical band about 1/2 as long as broad or more 36 



36. Tetrasporangia initially secund, mainly abaxial, later 

 whorled and somewhat involucrate; with descending 

 rhizoidal appendages from some of the inner cortical 



cells lying against the axial cells 



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



36. Tetrasporangia initially secund, mainly adaxial, later 

 whorled, slightly involucrate; without rhizoidal append- 

 ages from the cortical cells C. gardneri Kylin 



37. Plants smaller, the lower nodes rarely exceeding 130 {x in 



diam 38 



37. Plants larger, the lower nodes 150-450 /x in diam 41 



38. Upper internodes ordinarily less than 3 times as long as 



cortical band; adult nodes of more than 2 tiers of cells.... 39 



