76 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



parts flat, narrowly ligulate, 180-230 fx thick, 900-1100 fi wide, openly 

 pinnately branched at very irregular intervals, the branches of 2-3 orders, 

 but of such variable length as to show no regular branching pattern; 

 branches tapering to the base, all blunt-tipped and of about the same 

 breadth in all orders (except in old, proliferous, animal-damaged plants) ; 

 transection both of old and young portions showing an abundance of 

 rhizoidal filaments throughout the medulla and subcortical regions; 

 cystocarps and antheridia unknown; tetrasporangia borne irregularly in 

 narrow-elongate sori occupying the mid-portions of branches of the 

 ultimate and subultimate orders and bordered by a prominent sterile 

 margin. 



Type: Holotype is Dawson 3551, Nov. 20, 1946, on sheet 54672 

 including vial 2125 and slides 1311-1314 in HAHF. 



Type locality: On intertidal rocks near Puerto San Carlos on 

 Bahia de San Francisco, vicinity of Guaj^mas, Sonora, Mexico. 



The irregularity of length and spacing of branches, the nearly uni- 

 form width of branches of all orders, the abundance of rhizoidal fila- 

 ments both in the medulla and in the subcortex, and the large, narrow- 

 elongate tetrasporangial sori mark this species as distinct among the 

 gelidia of medium size along Pacific Mexico. 



Pterocladia caloglossoides (Howe) comb. nov. 

 Plate 6, fig. 1 



Gelidium caloglossoides Howe, 1914, p. 96, pi. 34, fig. 7, pi. 35, fig. 

 l-12;Hollenberg, 1942, p. 534. 



Thalli small, creeping, repent or in part erect, to 6 mm. high, flat- 

 tened throughout, consisting of a ligulate, creeping portion about 500 /x 

 wide attached at close intervals to the crustose coralline substrate by 

 small discs, with 1-3 divaricate branches arising from the thallus mar- 

 gins on either side of these nodes, these branches in part repent and in 

 turn producing discs and lateral branches, and in part erect or ascending, 

 usually simple, ligulate or linear-lanceolate, 300-500 /a wide with atten- 

 uate or rather acute tips; transection showing a cortex of 3-4 layers of 

 successively smaller pigmented cells and a medulla of a single (or ir- 

 regularly double row) of relatively large, thick- walled cells in part 

 surrounded by groups of straight rhizoidal filaments; tetrasporangia 

 borne in regular V-shaped rows in sori on somewhat expanded tips of 

 erect branches ; cystocarps unilocular, borne singly or in series of 2-3 

 on erect branches, bulging about equally on each side of the fertile blade ; 

 antheridia not seen. 



