1919J Sctchell-Gardner : Myxophyceae 71 



4. Phormidium lucidum (Ag.) Kuetz. 



Plate 1, fig. 4 



Trichomes bright blue-green, floating separately while in the free 

 motile stage, later forming dense entangled flocculent masses of dull 

 blue-green color, attached to soil along the margin of a pond or float- 

 ing, slightly but definitely constricted at the joints, 7-8/a diam. ; 

 sheaths quite mucous and more or less diffluent, apices straight, very 

 sliglitly tapering; cells 2-2.5|U. long; end cell rounded, calyptrate and 

 with thickened end walls; protoplast with two layers of fine granules 

 at the cross walls. 



Growing in warm salt water. Oakland, California. 



Kuetzing, Phyc. Gen., 1843, p. 194; Gomont, Monogr. des Oscill., 

 1892, p. 179, pi. 5, figs. 11, 12 (1893, p. 199, Repr.). OscUlatoria 

 liicida Agardh, Aufzahlung, in Flora, vol. 10, 1827, p. 633. 



The type of Phormidium lucidum is credited to Carlsbad and as 

 having grown on walls exposed, at least intermittent!}^, to steam. 

 The specimens referred to the species from our coast grew in warm 

 salt water in the Key Route pool at Oakland, California, and are per- 

 haps rather thermal than marine. The species also has been found 

 in a salt marsh near the Key Route pool, in shallow ditches made 

 warm by the sun. The description given above has been framed 

 to fit our plant, but differs from that of Gomont only in the matter 

 of color and thickness of the layer. In ours the color is bright blue 

 and the layer thin. In both these respects no. 127 of Kuetzing 's 

 Decades {Oscillaria lucens Kuetz.), which Gomont has cited as genuine 

 Ph. lucidum, agrees fairly well with our plants. 



5. Phormidium submembranaceum (Ard. and Straff.) Gomont? 



Stratum membranaceous, coriaceus, dark green, trichomes without 

 sheath, embedded in an amorphous mucus, constricted at the joints, 

 5/i, diam. ; apices of trichomes straight, long and gradually tapering, 

 capitate ; cells 4— 10/x long ; terminal cell provided with a depressed 

 conical calyptra; protoplasm homogeneous. 



Upper littoral belt. San Francisco Bay, California. 



Gomont, Monogr. des Oscill., 1892, p. 180, pi. 5, fig. 13 (1893, 

 p. 200, Repr.) ; Collins, Holden and Setchell, Phyc. Bor.-Amer. 

 (Exsicc), no, 1162. Oscillaria suhmcmhroinacea Ardissone and Straf- 

 forello, Enumer. d. Alg. di Lig., 1877, p. 66. 



