624 University of California Publications in Botany [Vol.8 



Nereocystis Luetkeana (Mert.) Post, and Rupr. 



Stipe very strong and elastic, 20-25 m. long, 1-1.5 cm. thick below, 

 the hollow portion, or pneumatocyst, 3-4 m. long, 15-17 cm. broad; 

 sporophjdls 25-40 in number, 3-4.5 m. long, 6-15 cm. broad ; sori in 

 large, irregular, promiscuously distributed areas on both sides of the 

 sporophylls. 



Growing on rocks and epiphytic in water 5-25 m. in depth. Extend- 

 ing from the Shumagin Islands, Alaska, to Santa Barbara, California. 



Postels and Ruprecht, Illus. Alg., 1840, p. 9, pis. 8, 9 ; Setchell 

 and Gardner, Alg. N.W. Amer., 1903, p. 268 ; Setchell, Kelps of the 

 U. S. and Alaska, 1912cf:, p. 158 ; Farlow, Anderson and Eaton, Alg. 

 Exsicc. Amer.-Bor., no. 116 ; Collins, Holden and Setchell, Phyc. Bor.- 

 Amer. (Exsicc), no. X; Tilden, Amer. Alg. (Exsicc), no. 237. 

 Nereocystis priapus (Gmel.) Saunders, Alg. Harriman Exp., 1901, 

 p. 431. Fucus Lu.etkea.nus Mertens fil, in Linnaea, 1829, p. 48. 



The "Bull Kelp," as it is frequently called, is an annual plant, 

 grows in beds of greater or less extent, rising from even 10-12 fathoms 

 of water, particularly extensive in the Puget Sound region and is an 

 available source of potash salts and other substances. It is one of our 

 largest and most striking seaweeds. We are extremely disinclined to 

 adopt the binomial Nereocystis Priapus, although by the process of 

 exclusion its application to our plant may seem to be extremely 

 plausible. The Ulva Priapus Gmelin (1786, p. 231, pi. 31, fig. 2) was 

 neither well described nor convincingly illustrated. Its locality is in 

 doubt. Probably it is either Nereocystis or Pelagophycus, and more 

 probably the former than the latter. We have neither seen nor heard 

 anything of the type specimen. 



51. Postelsia Rupr, 



Holdfast of stout branched hapteres ; stipe large, cylindrical and 

 hollow, bearing a group of pendent blades on short, solid dichotomous 

 branches at its summit. 



Ruprecht, Neue Pflanzen, 1852, p. 19 (75). 



Postelsia is a unique, monotypic genus of algae, confined as at 

 present known to the temperate waters of the west coast of North 

 America. Its relation to Nereocystis has just been discussed. The 

 date of publication depends upon the date of issue of the separate 

 papers which have 1852 on the title page, thus seeming to antedate 

 Areschoug's genus Virginia. 



