t-OP, v;: „. THE BOTANICAL MAGAZINE. .. . [Vol. xxtjc.no. sn. 



Locality. Oshoro, near Otaru Bay (!). 



Distribution. Europe ; New England coast of N. America ; 

 Jamaica. 



Porphyra linearis Grev. 



Alg. Brit. p. 170, PI. 18.-Kutz.: Spec. Alg. p. 691.-J. Ag.: Till 

 Alg. System. VI, p. 71, Tab. II, fig. 67.-Kutz.: Tab. Phyc. XIX, 

 Taf. 79, fig. g-i. 



Harvey proposed to reduce the present species to a syno- 

 nyme of P. vulgaris regarding it to represent a winter form 

 or a high tide form of the latter. Still, there have been some 

 authors who mentioned this species in an independent position, 

 though without any particular comment to disprove Harvey's 

 observation. 



In Alar. Alg. of Denmark, Part I, Rosenvenge stated that 

 P. linearis Grev. should be brought to under P. umbilicalis J. 

 AG. The paper is illustrated with photographic plates of 

 various forms of what he has taken as the latter species. 



My own observations on various species of Porphyra and 

 Wildemania on our coasts lead me to conclude that some 

 distinct species of both genera, especially of P. umbilicalis, P. 

 laciniata, etc., have narrow and cuneate form while yet young 

 or when grew at high water mark. This form in general out- 

 line agree equally well to P. linearis Grev. Both Harvey's 

 observation and Rosenvenge's statement, therefore, hold good 

 at the same time. On the other side, I am quite sure that 

 there is on our coasts a fixed form of Porphyra which keeps 

 all the characters of P. linearis Grev. for the whole life and 

 under any condition of habitat. In this form, the carpogonal 

 or the antheridial area is always strictly marginal, gradually 

 fading towards the meridional region of the frond. 



One of the figures of P. umbilicalis J. Ag. f. linearis given 

 by Rosenvenge in Plate II of the above mentioned work has 

 the antheridial area running along the margin but with remark- 

 ably sharp boundary between the vegetative area. This is 

 undoubtedlv a shallow water form of what he has illustrated 



