NO. 1 DAWSON: MARINE RED ALGAE OF PACIFIC MEXICO 45 



Spermothamnion snyderae Farl. var. snyderae 



PL 16, fig. 3-5 



Farlow 1899, p. 74; Dawson 1945, p. 67; Dawson 1949, p. 220; Dawson 1950, 



p. 155, fig. 24-25; Dawson 1951, p. 53; Dawson, Neushul & Wildman 1960, p. 



80, pi. 36, fig. 1-2. 



Thalli 1-3 (5) cm. tall, consisting of erect, finely hair-like filaments 

 from prostrate filaments attached by rhizoids with discoid ends; erect 

 filaments rather sparsely, mostly unilaterally branched, seldom with more 

 than 3 orders, 50-110 [x in diam., of cells mostly 5-7 (10) diameters 

 long; branches of successive orders of approximately the same breadth, 

 the ultimate ones about 0.7 times the diameter of basal ones; cystocarps 

 without an involucre, forming a loose terminal cluster 350 jx in diam.; 

 tetrasporophytes with polysporangia only, these borne terminally on 

 short, simple or compound branchlets in lower and middle parts of 

 erect filaments; polysporangia broadly ellipsoidal, 95-130 /.t long, 75-120 

 fi in diam., with 8-32 (usually 12-16) polyspores; spermatangia 

 forming cylindrical, compact, sessile heads about 150 \x long, 50 [x in 

 diam. arranged in short adaxial series on 5-7-celled, incurved, fertile 

 branchlets in middle and upper parts of plants. 



Type: Not specifically designated, represented by collections 

 of Mrs. Snyder, Mrs. Bingham, Mr. Cleveland, in the Farlow Herbarium 

 of Harvard University. 



Type locality: Not specifically designated: "Santa Cruz, Santa 

 Barbara, San Diego, Calif." 



Mexican distribution: Pacific Baja Calif. — D. 242, 279, Cooper 

 823, near Punta Descanso; D. 101, Cabo Colnett; D. 8890, Punta Baja; 

 Williams 5/24/46, Isla San Martin; D. 10550, Punta Norte, Isla Cedros; 

 D. 2847, near Punta Santa Rosalia; D. 13351, Punta Thurloe; D. 9538, 

 Punta Abreojos; D. 9213, 9173, Bahia Asuncion; D. 13291, Isla 

 Margarita. Gulf of Calif.— T). 852, Isla Jorge; D. 759, Isla Patos; D. 

 717, Puerto Libertad; D. 610, Ensenada de San Francisco. 



The Gulf of California specimens are generally smaller and more 

 delicate than those from the outer coast and have usually solitary, 

 pedicellate polysporangia rather than groups of two to six, but inter- 

 mediate conditions have been observed along southern Pacific Baja 

 California which indicate that the range of the species extends into the 

 cooler, northern Gulf of California and includes these more delicate 

 forms. In that region the plant seems to be a winter annual, for, from 

 Guaymas to Isla Jorge, it has been found only in February. 

 Spermothamnion snyderae var. attenuata var. nov. 



Varietas speciei similis sed tenuior, 1 cm. alt., axibus infra 50-80 fi diam., 

 supra ad 15-12 /x diam. attenuatissimis factis. 



Like the species but more delicate, 1 cm, high, the axes 50-80 fx in 

 diameter below and becoming remarkably attenuated to 15-12 /x in 

 diameter above. 



