302 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



referred to that species. They dififer from other Gulf species of the genus 

 by their discoid holdfasts and smooth, attenuated lower parts of the 

 blades. 



MacDougal, Puerto Libertad, Sonora, May 4, 1923 (with Gigartina 

 MacDougalii) ; D. 91, on rocky shore, Turner's Island, Jan. 



Gigartina Johnstonii sp. nov. 



Gigartina Chauvinii Setch. & Gard. (not of Montagne), 1924, p. 744, 



pis. 46b, 70. 



Frondes 12-25 cm. altae, complanatae 5-12 (-16) mm. latae, basim laxe ramoso 

 stoloniferae ; laminis primariis e stolonibus orientibus, secundariis tertiariisque 

 marginalibus; marginibus omnibus pinnulis simplicibus vestientibus ; discis lami- 

 narum projecturis papillatis indutis; apicibus acutis. 



Plants 12-25 cm. high, of complanate blades 5-12 (or 16) mm. broad 

 arising from a holdfast composed of a loose, branched, stoloniferous tan- 

 gle; primary blades arising as branches from the stolons; secondary and 

 tertiary blades successively smaller and all marginal; all margins with 

 conspicuous acute, simple or branched, spinose pinnules; blade surfaces 

 with shorter, more papillate projections; tips all very acute; branches 

 narrowed but not conspicuously constricted at bases. 



Type: D. 436, lower littoral rocks, San Esteban Island, Feb. 5, 

 1940. Herb. AHF no. 42. 



A comparison of specimens from the Gulf collections of this plant 

 with Peruvian examples of Gigartina Chauvinii has revealed that they 

 are not identical and that the Mexican plants are worthy of a distinguish- 

 ing name. 



The species is common on lower littoral rocks in the upper Gulf and 

 is known from the following stations: D. 92 (117 young). Turner's 

 Island, Jan.; D. 189 (207 young), Puerto Refugio, Jan.; D. 311, Gon- 

 zaga Bay, Jan.; D. 436, San Esteban Island, Feb.; J. 53, April; J. 101, 

 Georges Island, April. 



Gigartina pectinata sp. nov. 

 Plate 64, Fig. 1 



Frondes 5-30 cm. extendentes, laxe per extensiones papillarum superficium 

 inferarum aut per stolones parvas ramosas affixae; segmentis frondium angustis, 

 complanatis, primariis circa 3 cm. latis, distiche 3-plo ramosis, in ordine angustior- 

 ibus curtisque, apicibus acutis ; partibus latioribus ramorum, pinnulis copiose mar- 

 ginalibus, tenuibus, pectinatis. 



