98 



point of view as myself as to the arrangement and phylogenetic re- 

 lationships of the different tribes, subtribes and genera. Rejecting 

 Chorda and Adenocystis, as members of the Laminariaceae, Reinke 

 (loc. cit., pp. 9 and 52) argues for a monophyletic origin of the 

 whole family. The embryonal and postembryonal stages seem to sup- 

 port this view. Ali the members pass through distinct laminarioid 

 stages and even such seemingly aberrant forms as Thalassiophyllum, 

 Eisenia, and Hedophyllum subsessile (cfr. Setchell, Univ. Calif. Pub. 

 Botany, voi. 2, pp. ii5 et seq., 1905) have been shown to pass 

 through forms similar to simpler members ot their subtribes, as well 

 as even Arthrothamnus (cfr. Yendo, Bot. Mag., Tokyo, voi. 17, 

 pp. i65 et seq., 1703), while in their earlier stages they pass also 

 through the stili simpler laminarioid stages. When our knowledge 

 shall have become more complete, we shall probably have a reaso- 

 nably perfect series of developments connecting the various lines of 

 descent from some common laminarioid ancestor. Pterygophora, 

 therefore, in my opinion, must be alarioid Tather than laminarioid, 

 since its complexity of plant body arises by the outgrowth of sporo- 

 phylls from the lower portion of the transition place as is the case 

 in Alaria and in no other genus. Consequently, I cannot agree with 

 Mac Millan that it may be placed either with the Laminarieae or the 

 Alariideae (loc. cit., p. 739 et preced.), since it seems to me that the 

 various resemblances to Laminaria pointed out by him neither make 

 a good case, since they may be found also in some Alarias (cfr. also 

 Setchell and Gardner, loc. cit, p. 271), nor can they hold when com- 

 pared with the convincing evidence from the origin of the lateral 

 pinnae or sporophylls. 1 realize, however, that the less differentiated 

 midrib, the longer and perhaps less differentiated sporophylls argue 

 a lower membership in the Alariideae and consequently slightly clo- 

 ser approach to the originai laminarioid ancestor and this is made 

 even more dose than has been apparent hitherto by the discovery 

 that the biade assists in the hearing of sori. Yet, the alarioid type 

 is so pronounced in Pterygophora that there seems to be no reason 

 for associating it intimately with any other genus than Alaria, in 

 the subtribe Alarieae, of the tribe Alariideae. 



Alaria marginata P. & R. has been, thus far, a « species inco- 

 gnita » upon the western coasts of North America. In the originai 



