248 IP s te I s i a 



RENFREWIA GEN. NOV. 



Hold fast simple, discoid, ivithout haptera 

 arising on the stipe; sari extremely irregular; 

 tissues little differentiated; lamina plane, entire, 

 without prolijerations, unbranched. This genus 

 is separated from Laminaria because of its 

 simple discoid holdfast without haptera which 

 toiijether with its small size and evident sim- 

 j)licity of structure marks it as one of the most 

 primitive of kelps. The absence of branching 

 ha|)tera arising around the primitive discoid 

 holdfast and taking its place does not seem 

 at first thought a very striking character. But 

 it signifies a difference in the structure of the 

 plant fully as profound as the absence of a 

 stipe which was considered sufficient ground 

 for the separation of Hedophyllum; or a fold- 

 ing and irregular growth in the lamina which 

 differentiates Pleurophycus from Laminaria. 

 There are two species previously described as 

 Lam in arias which have simple holdfasts, Lami- 

 naria solididgula Agardh and Laminaria yezzoen- 

 sis Miyabe. The relations of these to the 

 present species as well as its relation to other 



