84 AKT. 12. K. YENDO. 



narrowly linear, costated and serrated leaflet, while others are 

 simply mucronated at the apex. 



Receptacles are complanated, clavated or spathulated, often 

 attenuated above, ending at the base in a short slender stalk. 

 They are disposed in a panicle or raceme on the final ramulets 

 of the upper branches. Receptacles of both sexes have a similar 

 external appearance. 



Remark on the synonymy. The present species is prone to 

 a considerable variation in its vegetative organs, according to the 

 condition of the environment and the season. The characteristic 

 duplicato-serrated leaves are often obliterated even in the spring 

 forms. In younger individuals, as above described, they are 

 often entirely wanting. Hence the morphological value of the 

 leaves in specific determination is sometimes very slight. The 

 matured plants without the characteristic fulcrant leaves are, 

 indeed, often liable to be confounded with Sargassum tortile. 

 The distinction between these two species will be discussed in 

 the next chapter. 



On consulting the original diagnosis of Sargassum coryne- 

 carpum Harv., I was led to strongly suspect that it had been 

 based on a specimen of Sargassum serratifolium which had lost 

 its fulcrant leaves by age. The photograph of the original 

 specimen of the former species showed that Harvey's plant 

 was undoubtedly an old specimen of the present species, with 

 some basal leaves still undetached but having lost the fulcrant 

 leaves on all branches. J. Agardh^^ referred a plant to Sar- 

 gassum corynecarpum Harv., but his plant belongs to a quite 

 different species, as may be easily seen by comparing the descrip- 



r' 



1) Anal. Alg. Cont. III. p. 57. 



