14 AKT. 1-2. K. YEXDO. 



SPECIES. 



FUCUS (Touni.) L. 

 IPucus evanescens Ag. 



Plate T. Fi.ir. 1-2. 



Ag.: Icon. Alg. iued. t. 132.— /f/.: Spec, 1. p. 92.— J. Ag.: .Spec. 1. p. 210. 

 —Id.: Spetzb. Alg. II. p. 40.— Farlow: Alg. of New Engl, p. 101.— 

 Kjellm,: Oni Beringliafv. Alg, p. o4. — Id.: Alg, Arct, Sea. p. 202. — 

 Ki-TZ.: Tab, Phyc, X. Taf, 42. I. {non bona).—T>E Toni: Syll. Alg. III. 

 !>. 201, — Okam.: Eniuner. Alg. of Jap. }). 1.37. — Setcii. anil Gard.: 

 Alg. X. W. Anier. p. 2.S1. 



= Fucus vcsiculosHS var. cvancsccns Küt/..: Si)ec. }>. .589, 

 = Fucus vcsiculosus PosfT, et Rupr.: 111. Alg. t. 30. 



The present species abounds in tlie northern j^arts of the 

 Pacific as well as of the Atlantic Ocean. More than a dozen 

 forniic have been described by Kjellman from both localities, 

 and Setciiell and Gardner'^ added two more from the north- 

 west coast of North ^Vmerica. Kjellmax""' himself, however, 

 observes that the formœ lie described ** are certainly connected 

 by numerous intermediate forms, but they deserve however to 

 be mentioned specially, because they show the limits and direc- 

 tions of the species and differ somewhat with regard to biology 

 and geographical distribution." I am strongly of the belief that 

 some of his forma' are nothing but extreme cases of one and the 

 same species, due to age and i)lacL' of growth. The ])readth and 

 texture of the segments of the fronds, and especially the caules- 

 cence or non-caulescence of the plants, are characters that are 

 never reliable. Generally speaking, young and sterile individuals 

 have the segments mostly winged down to the l)asal ones, while 



1) Setciiell iukI (Jaiidnek: Algic of N. W. America, p. 283. 



2) Kjellman: Al-jiL- vC llic Aiclit: S(.a. p. '20o. 



