96 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



Myriogramme caespitosa Dawson 

 PL 47, fig. 4 

 Dawson 1949, p. 19, fig. 8; Dawson, Neushul & Wildman 1960a, p. 26. 



Thalli caespitose, about 1 cm. high, densely, congestedly branched 

 from the base, consisting of several thick, membranous, essentially non- 

 stipitate blades arising from a small, irregularly fleshy holdfast, the 

 blades joined together by small accessory attachment discs; blades 

 ruffled and lobed, 5-8 mm. broad, with smooth margins and rounded 

 terminal lobes, unistratose except in basal parts, the thallus cells angular, 

 25-50 (70) [x in diam. as seen in surface view; cystocarps 250-400 /a in 

 diameter, with a conspicuous, rostrate ostiole. 



Type: Hubbs 47-96d, April 30, 1947, in Herb. A. Hancock 

 Foundation (26867). 



Type locality: On the holdfast of Macrocystis found floating in 

 San Miguel Passage off Santa Rosa Island, California. 



Mexican distribution: Pacific Baja Calif. — -D. 20400, Isla Asun- 

 cion, 6-12 m.; D. 20190a (Neushul), off Punta Entrada, Isla Magdalena, 

 13 m. (Both these collections were growing on Macrocystis holdfasts.) 



Myriogramme osorioi Dawson 



PI. 47, fig. 1-2 

 Dawson 1950a, p. 158, fig. 18-19. 



Thalli caespitose, to 3 cm. high, from a clasping, branched, dacty- 

 loid holdfast from which arise 1 to several stipes about 800 p. in diam., 

 in turn giving rise 3-5 mm. above the bases to expanded, broad, membra- 

 nous blades, palmately deeply divided, the lobes mostly 4-5 mm. broad, 

 entire, but commonly lacerated; stipe extending as a midrib only a little 

 way, then fanning out and fading in the lower part of the blade; blades 

 monostromatic in upper parts and at the margins, 50 /x thick, di-tetras- 

 tromatic below and in the middle (extension of the stipe), broadly 

 rounded at the apices, without microscopic veins; growth marginal by 

 means of a group of apical initials; cells in surface view mostly elongate- 

 polygonal, 20-40 jx in greatest diameter; secondary blades stipitate, orbi- 

 cular at first, arising from the margins, the stipes, or from the surface 

 of the thickened mid-portions at the base of primary blades; tetrasporan- 

 gia borne on one side of the blade in large, circular or oval sori to 4 

 mm, in diam., occupying most of the middle and upper blade area; 

 sexual plants unknown. 



Type: Dawson 737, Feb. 18, 1946, in Herb. A. Hancock Founda- 

 tion. 



Type locality: Intertidal rock crannies, northeast side of Isla 

 Patos, Sonora. 



Mexican distribution: Gulf of Calif. — D. 1009, Isla Partida. 



