626 University of California Publications in Botany [Vol. 8 



vol. 7, p. 75, pi. 6). Pfeiffer (Norn. Bot., vol. 2, p. 823) quotes this as 

 the original publication, thus considering Virginia Palma-Maris of 

 Areschoug (lot: tit.) as antedating Ruprecht's Postelsia palmaeformis. 

 The Postelsia calif ornica of Guignard (loc. tit.) undoubtedly refers to 

 Postelsia palmaeformis, since he lists several other kelps of the 

 California coast along with this species. 



tribe 2. MACROCYSTEAE kuetzing (lim. mut.) 



Plants of the family Lessoniaceae having, in large part, unilateral 

 splitting, thus producing a scorpioid sympodial stipe. 



Kuetzing, Phyc. Gen., 1843, p. 348 ; Setchell, Kelps of the U. S. and 

 Alaska, 1912a,, p. 158. 



The Macrocysteae have regularly dichotomous splitting in the first 

 few divisions, but after that the splitting is unilateral. 



Key to the Genera 



1. Stipes solid 52. Macrocystis (p. 626) 



1. Main stipe hollow 53. Pelagophycus (p. 629) 



52. Macrocystis Ag. 



Holdfast of mature plants consisting of a large entangled mass of 

 dichotomously branched hapteres or of creeping flattened rhizomes 

 giving off lateral hapteres as well as erect fronds ; stipe in the juvenile 

 plant forking 1-3 times dichotomously, forming several main stipes, 

 later the branching is unilateral; blade at first splitting equally, but 

 soon the terminal bladderless falcate blade splitting unequally ; meri- 

 stematic transition region at the juncture of the stipe and falcate 

 blade ; the mature blades undivided bearing a bladder at their base and 

 the sori on both sides ; perennial. 



Agardh. Sp. I, 1820^ p. 46. 



The species of Macrocystis are not well marked off from one another 

 but the genus, with its unilateral splitting and its long cylindrical 

 stipe, unbranched above the basal dichotomies, and its large and com- 

 plicated holdfasts or overlapping massive "rhizomes," is distinct 

 from any other. 



Concerning the position of the sori in members of this genus, 

 Skottsberg (1907, pp. 104-108) and Howe (Mar. Alg. Peru, 1914, 

 pp. 62, 63, 65, 66) have reviewed the literature and the facts most 

 thoroughly. The sori, in our species, seem confined to the basal leaves, 

 and specimens are not commonly collected. The sori do not seem to 



