HOW TO KNOW THE SEAWEEDS 



29b Thallus without such a gradation from a multiseriate to a uniser- 

 iate condition in the ultimate ranks of branches. Fig. 48 30 





^ 



Figure 48 



Fig. 48. Dasya sp. 



A single lateral 

 branch as separated 

 from the corticated 

 main axis showing sev- 

 eral ranks of uniseri- 

 ate branchlets, and 

 several conical anthe- 

 ridial branchlets. These 

 uniseriate branchlets 

 are here much magni- 

 fied, and to the naked 

 eye appear as very- 

 fine hairs both in Da- 

 sya and in ^lanqelia. 



30a Main axes corticated (at least to some extent in lower parts) by 

 means of the growth of filaments from cells at the nodes. Fig. 49; 

 branchlets arising only at points of junction of axial cells 31 



Fig. 49. CaWiXhammon sp. 



A small piece of a plant showing 

 branching from two nodes and an early 

 stage in development of cortication by 

 growth of descending filaments from 

 the nodal cells. X 85. 



Figure 49 



49 



