1925] Setehell-Gardner: Melanophyceae 633 



develop in the transition region in pairs year after year as the meri- 

 stcin moves forward until the plant is dislodged and dies. Griggs 

 (1909) was the first to properly describe the origin of the sporophylls. 



The branching is strictly dichotomous and is accomplished by the 

 splitting of the blades longitudinally through the midrib, the splitting 

 beginning at the transition region and progressing to the outer end. 

 A new ala develops on each half blade as the splitting proceeds. 



Less&niopsis UttoraLis and Postelsia palmaeformis are the most 

 typical examples of cumatophyte species of our algal flora. No surf 

 seems to be too rigorous to hinder their optimum development. The 

 former usually occupies a belt lower down than the latter. Apparently 

 it is unable to withstand the desiccation incident to long exposure to 

 the air. 



family 22. ALAKIACEAE fam. nov. 



Fronds simple or irregularly branched, with terminal blades and 

 lateral outgrowths, the latter arising at the transition places ; terminal 

 blade with or without a midrib or central thickened area, plane or 

 rugose, with or without cryptostomata, or tufts of hairs ; otherwise as 

 in the order. 



The family of the Alariaceae is intended to include all the genera 

 whose species possess sporophylls, either kinetic or potential, arising 

 as outgrowths of either stipe or blade and arising at the transition 

 place, with the exception of the genus Lessoniopsis, described above. 



Key to the Tribes 



1. Mature outgrowths confined to the stipe 1. Alarieae (p. 633) 



1. Mature outgrowths not as above 2 



2. Mature outgrowths confined to the blade 2. Ecklonieae (p. 645) 



2. Mature outgrowths on both stipe and blade 3. Egregieae (p. 647) 



tribe 1. ALARIEAE setchell 



Members of the Alariaceae with sporophylls only on the stipe. 



Setchell, Kelps of the U. S. and Alaska, 1912a, p. 160. 



The Alarieae are confined to the northern hemisphere, occurring 



in the Arctic, the north Atlantic, and the north Pacific oceans. The 



outgrowths at the transition place are arranged on the stipe and are 



usually highly specialized sporophylls, bearing sori, maturing and 



disintegrating. 



Key to the Genera 



1. Midrib distinct; sporophylls definitely limited in growth 56. Alaria (p. 635) 



1. Midrib indistinct; sporophylls more or less indefinite in growth 



55. Pterygophora (p. 634) 



