304 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



Ghoreocolacaceae 



With a single species in the Mexican flora. 



Ghoreocolax polys iphoniae Reinsch 



Reinsch 1875, p. 61, pi. 49; Newton 1931, p. 424, fig. 254, A-F; 

 Smith 1944, p. 255; Dawson 1945c, p. 61 ; Hollenberg 1948, p. 159. 



Thalli parasitic on Polysiphonia, forming small, pale brownish, 

 globose to hemispherical, simple or lobed cushions of variable size, 0.6- 

 2.0 or to 4.0 mm. in diameter; tetrasporangia cruciate, immersed in the 

 cortex, variable in size, mostly about 45 ju, long, 28 /a wide; cystocarps 

 several in a cushion, conceptacle-like, ostiolate; antheridia superficial 

 from the outer layer of the cushion. 



Type: Holotype not designated, and whereabouts of the original 

 material, if extant, unknown to the writer. It is not in the Herbarium 

 at Kew, England. 



Type locality: Parasitic on Polysiphonia fastigiata, Atlantic 

 Coast of North America. 



Mexican distribution: Pacific Baja Calif. — D. 16-45 (in Herb. 

 U.C.) on Polysiphonia collinsii, near Cabo Colnett, Mar. 



Only a few cystocarpic examples have thus far been detected in the 

 Mexican collections, although it is expected that this small parasite may 

 prove to be frequent when examinations of large numbers of Polysiphonia 

 plants are made. 



