1919] Setchell-Gardner : Myxophyceae 67 



12. Oscillatoria chalybea (Mert.) Gomont 



Trichomes pale steel-blue, dark blue-green in mass, fragile, usually 

 straight, but at times slightly spirally twisted ; moderately constricted 

 at the joints, 8-13/x diam. ; briefly, or long and gradually attenuate, 

 one to a few apical cells uncinate ; cells quadrate to 2-3 times shorter 

 than the diameter, protoplast finely granular, with few, scattered, 

 angular, ref ringent granules ; dissepiments non-granular ; apical cells 

 obtuse, non-capitate, non-calyptrate. 



In ponds of brackish water. Wliidbey Island, Washington and 

 West Berkeley, California. 



Gomont, Monogr. des Oscill., 1892, p. 232 (1893, p. 252, Repr.). 

 OscillarM chalybea Mertens, in Jiirgens, Algae aquaticae, Decas XIII, 

 no. 4, 1822 (determined by Gomont). 0. Okeni Setchell and Gardner, 

 Alg. N.W. Amer., 1903, p. 184 (not of Agardh). 



This species is widely distributed, occurring in fresh waters, 

 thermal waters, and brackish waters. It is found in salt marshes both 

 in the Puget Sound region and in the region of San Francisco Bay. 

 The form found in both these regions is the typical form (var. genuina 

 Gomont). The tip, while characteristic, varies in its more sudden 

 or more gradual attenuation, and the cells are frequently equally long 

 and thick. Certain filaments seem straight at the tip and bear some 

 likeness to 0. simpUcissima Gomont. 



SUBFAMILY 3. LYNGBYEAE kuetz. 



Trichomes simple or branched, each enclosed within a more or less 

 firm or diffluent gelatinous sheath. 



Kuetzing, Phyc. Gen., 1843, p. 179 (char, emend.) ; Forti, in De- 

 Toni, Syll. Alg., vol. 5, 1907, p. 217 (lim. mut.). Lynghyoideae 

 Gomont, Monogr. des Oscill., 1892, p. 95 (1893, p. 115, Repr.). 



We have quoted Forti under the subfamily Lyngbyeae because his 

 idea of the limitations of the subfamily is nearest to, although not 

 exactly, ours. We include the genus Plectonema in addition to those 

 named by Forti. Our subfamily differs from the subtribe Lj^ng- 

 byoideae Gomont by the inclusion of Phormidimn. 



17. Phormidium 



18. Lynghya 



19. Plectonema 



20. Symploca 



