62 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



Type locality: South Bay, Isla Guadalupe, Pacific Mexico. 



Mexican distribution: Pacific Baja Calif. — D. 10560, Punta 

 Norte, Isla Cedros, Oct. Gulf of Calif. — D. 1016, Isla Partida, Feb. 

 (sterile) ; D. 803a, Isla Patos, Feb. (sterile) ; D. 726-40, Isla Turner, 

 July (cystocarpic) ; D. 1353, Bahia de Los Angeles, Apr. (sterile). 



This small species is readily distinguished by its rhizoidal filaments 

 which are not longitudinally arranged, but interlace in all directions. Its 

 tendency toward flabellate branching is also distinctive. 



The Isla Partida specimen bears several tubercular nodules which 

 have the appearance of a parasitic red alga. No reproductive structures 

 have been found in them, however, and their identity has not been 

 ascertained. 



Gelidium pusillum (Stackhouse) Le Jolis 



Le Jolis, 1863, p. 139; B<^rgesen, 1927, p. 83, fig. 44; Feldmann & 

 Hamel, 1936, p. 112, fig. 19A-C, 20; Dawson, 1944, p. 258, pi. 42, figs. 

 1-6; Taylor, 1945, p. 152; Dangeard, 1949, p. 148, figs. 9n-q, s. Fucus 

 pusillus Stackhouse, 1801, p. 17, pi. 6. 



Thalli 2-10 mm. high, tufted, pulvinate or variously matted, in pure 

 stands or intermixed with other small algae on rocks or on dead or living 

 barnacles or mollusk shells, consisting of creeping, stolonoid parts at- 

 tached at frequent intervals to the substratum by peg-like or discoid 

 adherent organs and giving rise to numerous erect branches, the latter 

 simple or variously sparsely and irregularly pinnately branched, usually 

 terete below but usually more or less prominently flattened above, 200- 

 700 {L wide and commonly about 100-120 /a thick, clavate in outline with 

 blunt and rounded tips, or more or less attenuated or flagellate ; thallus 

 in transection at the level of mid-parts of flattened blades showing a 

 limited medullary area of a few small, thick-walled cells scattered among 

 many, closely packed longitudinal rhizoidal filaments; tetrasporangial 

 sori occupying the whole of terminal parts of erect blades or their 

 branches ; sexual plants not known in the Mexican flora. 



Type: Holotype not designated and whereabouts of the original 

 material unknown to the writer. It is not among a few of Stackhouse's 

 specimens at the Linnean Society, London. 



Type locality: Sidmouth and Brighton, England. 



Mexican distribution: This extremely variable small plant 

 seems to occur throughout virtually the entire Pacific Mexican coast, 

 including the Gulf of California, from Islas Los Coronados and Isla 



