134 BOTANICAL GAZETTE [febrvAry 



Skottsberg has given a most careful and valuable discussion of the 

 relationships of the Lessonia group in the Phaeophyceae of his Sub- 

 antarktischen und antarhtischen Meeresalgen (Wiss. Ergebn. d. 

 Schwedischen Sudpolar-Exp. 4: Lief. 6. 1907) and takes up this 

 matter in that connection. His decision is to retain the species in 

 Nereocystis (/. c. 139). He seems to incline toward the view that 

 the splitting in Nereocystis is also unilateral. With this view, as 

 indicated above, I cannot find myself in agreement. I have examined 

 many, both older and younger, Nereocystis Luetkeana, with the result 

 that I find the splitting to proceed fairly imiformly dichotomously as 

 noted above. In Pelagophycus, on the contrary, the splitting is 

 decidedly unilateral and like that of Macrocystis. A yoimg plant, with 

 characteristic adult form though not of adult dimensions, is represented 

 in the photograph reproduced in connection with my paper. Skotts- 

 berg has remarked that there are five leaves on one branch and sLx 

 on the other. There were sk on each, but on one only the petiole 

 remains to show its position. In the specimen figured, the branching 

 has been absolutely unilateral after the first splitting, as is shown by 

 the fact that the leaves are single. In many specimens, however, 

 some of the lower leaves divide a second time, as happens constantly 

 in young specimens of Macrocystis, but not more than one or two 

 usually do this. In this, as in other characters, this plant is inter- 

 mediate between Nereocystis and IMacrocystis. From all the ex^idence 

 it seems to me best to keep the genus Pelagophycus, and to associate 

 it with the Macrocysteae under the tribe of the Lessoniideae. 



As has been shown above, Leman's name of Laminaria Porra is 

 the earliest binomial, which necessitates the new combination: 



Pelagopriycus Porra, comb. nov. 



Laminaria Porra Lenian. Diet. Sci, Nat. 23:189. 1822. 



Nereocystis gigantea kr^soh. Bot. Notiser 1876: 71. 

 Pelagophycus giganieus Aresch. Bot. Notiser 1881: 49. 



I desire to thank Mr. F. S. Collins of Maiden, Mass., for tran- 

 scripts of the reference of Leman and also that of LeGentil to 

 Porra. To F. J. Taggart, librarian of the Bancroft Library of the 

 University of California, I am indebted for assistance in obtaining 



LaPehou 



STVESSTTY OF Ca 



Berkeley 



