NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 137 



west of Punta Malarrimo, Oct.; Williams, 4/30/46, Laguna Ojos 

 Liebre (Scammon) Apr.; Johnson & Allanson, 2/11/50, Laguna de 

 San Ignacio, Feb.; D. 6634 Bahia Magdalena, Mar.; D. 640-40, San 

 Jose del Cabo, Feb. Gulf of Calif. — D. 519, Ensenada Bocochibampo, 

 Feb. Nayarit—D. 3702, Mira Mar, Dec. Guerrero— D. 3908, Aca- 

 pulco, Feb. ; Hubbs 46-239, Puerto Marques, Sept. 



Nothing was indicated in the original description of the habit of the 

 whole plant, although the form, branching and internal structure were 

 well described and illustrated. Through the kindness of Dr. Pierre 

 Bourelly of the Museum of Paris, I was able to obtain two small frag- 

 ments of the scant type material. These agree in all details with the 

 Mexican specimens cited here, all of which are from intertidal habitats. 

 The distinctive features of this plant are the tufted, erect habit, the 

 secondary pinnate branching, the slender, cylindrical, prominently an- 

 nulate segments with thin cortex, the unizonal genicula, and the strongly 

 projecting, superficial, hemispherical conceptacles. 



Amphiroa annulata var. pinnata var. nov. 



Ad formam typicam speciei, at ramificatione dichotoma paene om- 

 nino suppressa; caulibus multis erectis percurrentibus, disperse, second- 

 arie, pinnate, multifarie ramificatis. 



Like the species, but the dichotomous branching almost entirely sup- 

 pressed, the numerous erect axes percurrent, sparsely secondarily, pin- 

 nately, multifariously branched. 



Type: Holotype is Dawson 3374, Nov. 9, 1946, in vial 2236 in 

 HAHF. 



Type locality: Intertidal pools, Cabeza Ballena, Baja Cali- 

 fornia, Mexico. 



'Additional material: D. 6834, Cabeza Ballena, Baja Calif., 

 Mar.; D. 3258, Punta Palmilla, Baja Calif., Nov. 



The three collections cited seem to have so much in common with 

 Amphiroa annulata, despite their distinctive branching, that they may 

 best be recognized only as variants of that species. They closely resemble 

 both the habit and internal structure of Amphiroa valonioides Yendo 

 (1902, pi. 4, fig. 1) but the branching appears to differ, the segments 

 to be shorter, and the annulations indistinct. Material for direct com- 

 parison with this latter plant is not available at this time. No examples 

 are present in Herb. Yendo, Tokyo University. 



