93 



Miyabe seems from Miyabe' s piate (loc. cit. pi. 12 and i3) certainly 

 to bave nuthing farther in connection with R. parvi/fa Griggs than 

 the discoid holdfast. There is nothing in Miyabe' s figures to indicate 

 that his species has anything primitive about it olhcr than its hold- 

 fast. The only daini, therefore, that the genus Renfrewia seems to 

 have to independence, is the possession of a discoid holdfast for 

 otherwise, as Griggs has constituted it, it possesses in its three spe- 

 cies complexities upon which other writers have altempted to found 

 segregation from the somewhat polymorphic, but nevertheless rea- 

 sonably compact genus Laminaria. In comparing the reason for se- 

 gregation of his Renfrewia from Laminaria to those which induced 

 me to separate Hedophyllum from the same genus (cfr. Setchell, 

 Zoe, voi. 5, p. 121, 1901), he seems to state that the only cliaracter 

 separating Hedophyllum is the absence of a stipe. As a matter of 

 fact, it is distinctly stated in the description that the giving off of 

 hapteres from the decumbent basai margins is one of the distingui- 

 shing characters of the genus. These basai margins continue to grow 

 and to give off hapteres which brings the relation of Hedophyllum 

 sessile very dose to H. subsessile, provisionally referred to the same 

 genus, and through the lattei" species also dose to the genus Ar- 

 throthamnus, especially when we take into consideration the H. spi- 

 rale Yendo (Botanical Magazine, Tokyo, voi. 17, p. 1 65, 1908). It 

 was this which led me to propose a separate tribe, Hedophylleae, 

 for the reception of Hedophyllum and Arthrothamnus (cfr. Setchell, 

 U. C. Pubi., Botany, voi. 2, p. 126, 1905). Similar considerations 

 induced the establishment of the genus Pleurophycus Setchell and 

 Saunders, the setting off of Cymathaere by J. G. Agardh, of Kjell- 

 manniella by Miyabe etc, since these plants seemed to belong to a 

 line of differentiation leading up to Agarum and Thalassiophyllum. 

 Renfrewia parvuìa, or Laminaria ephemera as it may be called in 

 accordance with my own ideas, seems to me to be a sort of vernai 

 species, a case of arrested development, similar to what happens to 

 certain individuai plants of Laminaria saccharìna in the socalled var. 

 Phyllitis Le Jolis. The form just mentioned, as a rule does not fruit, 

 but disappears before maturity, yet, in some cases, it does fruit while 

 yet retaining vernai characters which may certainly be compared with 

 those of L. ephemera (cfr. Setchell, Rhodora, voi. 2, p. x 23, 1900). 



