NO. 2 DAWSON: MARINE RED ALGAE OF PACIFIC MEXICO 283 



Tortuga, Mar.; Osorio-Tafall, Sept. 1, 1946, Isla Asuncion; D. 9156, 

 9157, Bahia Asuncion, Apr.; Osorio-Tafall, Sept. 1, 1946, Isla San 

 Roque. 



This species has had a most changeable nomenclatural status on both 

 sides of the Pacific. It is perhaps because of Okamura's unfortunate 

 recognition of this plant under Grateloupia that the identity of the 

 American with the Japanese plants has heretofore been overlooked. 

 Okamura's original illustrations excellently depict the habit, anatomy 

 and reproduction of this species. His figures correspond in all details with 

 the common plant which both Kylin and Doty described under different 

 names. 



The relatively remote, regularly dichotomous forkings, the sparse, 

 determinate, pinnate, secondary branchlets, and the presence of the 

 tetrasporic sori both in the terminal segments and in the secondary pinnae 

 are characteristic features, 



Zanardinula lanceolata (Harvey) J. DeToni 

 PI. 5, fig. 40; pi. 23, fig. 69 



J. De Toni 1936, n.p. ; Dawson 1949, p. 220. Gelidium lanceolatum 

 Harvey, 1830-41, p. 164. Prionitis lanceolata (Harvey) Harvey 1853, 

 p. 197, pi. 27, fig. A; Smith 1944, p. 246, pi. 57, fig. 1. Zanardinula 

 kylinii Doty, only as to Bahia Sur, Isla Cedros specimen interpreted by 

 Dawson 1952, p. 431. Prionitis filiformis Kylin, as interpreted by Taylor 

 1945, p. 209. Zanardinula linearis (Kylin) Papenfuss, as interpreted 

 by Dawson 1945c, p. 66. 



Thalli 20-45 cm. tall, deep, dull, reddish-purple in color, much 

 branched, the segments flattened, mostly 1.5-2.5 mm. broad, attached by 

 a simple disc; primary branching irregular, remote, the branches ± 

 uniform in width throughout although slightly narrowed at the base; 

 secondary branching pinnate, distichous, relatively dense, the pinnae 

 often at intervals of 2-3 mm. ; pinnae ± determinate in growth, lanceo- 

 late to linear-lanceolate, tapered to the base, mostly 0.5-2.0 cm. long, 

 seldom over 4 cm. long, sometimes deciduous from lower primary axes ; 

 transections of upper primary axes about 500 /a thick, and of secondary 

 pinnae about 200 /* thick, showing a dense, small-celled outer cortex, a 

 transitional, larger-celled inner cortex, and a dense medulla of inter- 

 twined, compacted filaments 5-12 ju, in diameter; outer cortex of anti- 

 clinal rows of 3-9 quadrate cells 3.0-3.5 //, in diameter; subcortex of 

 several irregular layers of rotund cells up to 30 /* in diameter, the largest 

 on the inside next to the medulla; tetrasporangia borne in nemathecial 



