1919] Sctchell-Gardner : Myxophyceae 91 



drical, slightly constricted at the dissepiments which are very distinct ; 

 terminal cell either blunt or acute conical ; heterocysts subspherical to 

 cylindrical, 3.5^.5/i diam., 5-7 /i, long; spores subspherical to broadly 

 ellipsoidal, 5.5-7/x. diam., 7-9/x long, catenate, developing centrifugally, 

 membrane smooth, hyaline. 



Forming a thin stratum, more or less continuous, on Ruppm mari- 

 tima. In pools in a salt marsh. West Berkeley, California. 



Setchell and Gardner, in Gardner, New Pac. Coast Alg. IV, 1919&, 

 p. 487. Anahae'Tia variabilis Collins, Holden and Setchell, Phyc. Bor.- 

 Amer. (Exsicc), no. 1209 (not of Kuetz.). 



Anabaena propinqua appears to be closely related to A. variabilis 

 Kuetz., but comparison with material of that species from Herbarium 

 Thuret contributed by Dr. Bornet (Herb. Univ. Calif, no. 100300) 

 shows that it differs in the smaller dimensions of all parts of the plant, 

 vegetative cells, heterocysts, and spores, which are also more nearly 

 spherical than in A. variahilis and have hyaline walls instead of brown. 



2. Anabaena variabilis Kuetz. 



Plate 8, fig. 8 



Filaments combined into a thin gelatinous stratum; trichomes 

 flexuous, mucous, 4r-^ix diam., terminal cell obtuse-conical; cells dolii- 

 form, 2.5-6ju, long, or at times subquadrate and deeply constricted at 

 the dissepiments; heterocysts spherical or oval, 6;u diam., 8/i long; 

 spores oval with truncate ends, usually seriate, 7-9/i. diam., 8-14/a long, 

 developing centrifugally from midway between the heterocj'sts, with 

 smooth brownish walls. 



Floating in quantity in bluish green gelatinous masses in brackish 

 pool. Presidio, San Francisco, December, 1895. Found in both fresh 

 and brackish waters. 



Kuetzing, Phyc. Gen., 1843, p. 210 ; Bornet and Flahault, Rev. IV, 

 1888, p. 226. 



This species has been found in brackish water only once with us, 

 but probably is to be found elsewhere than in San Francisco when 

 the various salt marshes along our coast are carefully explored. There 

 seems little doubt of the identity of the species although it is sterile. 

 It has been found in spore condition in fresh waters in our general 

 territory. 



