1919] Setchell-Gardner : Myxophyceae 87 



2. Microcoleus tenerrimus Gomont 



Filaments aggregated into dense, blue-green layers, or dispersed 

 among other species of algae, simple or sparsely branched; sheaths 

 ample, somewhat irregular, apices acuminate or open and blunt ; 

 trichomes dark olive green, moderately numerous within the sheath, 

 elongate, flexuous, somewhat loosely entwined, extremely constricted 

 at the joints, apices frequently long attenuate, 1.5-2/x thick; cells 

 2.2-6ju, long, witli occasional granules at the cross walls; apical cell 

 very acute conical, not capitate. 



Growing on mud in salt marshes. Puget Sound, Washington, to 

 central California. 



Gomont, Monogr. des Oscill., 1892, p. 355, pi. 14, figs. 9-11 (1893, 

 p. 93, Repr.) ; Setchell and Gardner, Alg. N.W. Amer., 1903, p. 188. 



The specimens referred to Microcoleus tenerrimus are so placed 

 with some doubt. The general characters agree but the cells are not 

 distinct, the dissepiments being somewhat obscured instead of appear- 

 ing hyaline and there are no evident constrictions. A further study 

 of living material is very desirable. 



3. Microcoleus Weeksii S. and G. 

 Plate 6, fig. 24 



Sheath thin, hyaline, gelatinous, irregular; trichomes 20-40 in a 

 sheath, loosely intertwined, aeruginous, not torulose, 7-8/a diam., ends 

 attenuated; protoplast homogeneous; cells 1.8-2.5/a long; end cell 

 acutely conical, neither capitate nor calyptrate. 



Growing on Griffithsia sp. in the lower littoral belt. Near Pacific 

 Grove, California. Collected by Mrs. J. M. Weeks, February 1, 1896. 



Setchell and Gardner, in Gardner, New Pac. Coast Alg. Ill, 1918a, 

 p. 470, pi. 40, fig. 24. 



In 1896 Mrs. J. M. Weeks sent some specimens of Griffithsia for 

 determination, and in making a microscopic examination of the 

 material there were detected specimeiLS of a Microcoleus which seemed 

 to be undescribed. The material being scanty was not named and 

 described at that time, but incorporated into the Herbarium awaiting 

 further investigation, and with the hope that more material might be 

 discovered. Since then, unfortunately, no more material has been 

 reported, but the species has been described since it seems very distinct. 



