208 



PHAEOPHYCEAE 



Sargassum, these leafy bodies serving not only as assimilatory 

 organs but also as floats. iVll the subsequent branches, which grow 

 in corymbose clusters from the base of the phylloclade, are fertile. 

 The genus is essentially confined to the warm waters of the tropics 

 and subtropics. 



Fig. 139. Turbinaria. 

 (After Oltmanns.) 



Portion of plant with sterile (s) and fertile (/) branches. 



Anomalae 



*Fucaceae: Hormosira (hormo, necklace; sira, a chain). Fig. 140. 



The sporophyte, which has the appearance of a bead necklace, 

 is composed of a chain of swollen vesicles (internodes) connected 

 by narrow bridges (nodes). Growth takes place by means of a 

 group of four apical cells, and these give oflF branches alternately in 

 a dichotomous manner, the branches usually arising at the inter- 

 nodes ; but apart from the discoid holdfast, there is no differentia- 

 tion into appendages comparable to those of the other Fucaceae. 

 The basal internode is soHd but all the remainder are hollow: the 

 nodes are also solid because they are composed solely of epidermis 

 and cortex. The sporophytes are dioecious, the conceptacles being 



