278 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



Reexamination of the type material of Prionitis kinoensis has revealed 

 the presence of cystocarpic and antheridial specimens. The study of 

 these, together with tetrasporic specimens from La Paz, has led to the 

 conclusion that they must be united with the species described by Setchell 

 and Gardner as Grateloupia acroidalea. However, the dense structure, 

 pinnate secondary branching, cartilaginous texture, and nemathecial 

 tetrasporangial sori of this plant indicate that the species may more 

 satisfactorily be recognized under Zanardinula than under Grateloupia. 

 The habit and transectional structure with its indistinct subcortex are 

 somewhat different from the usual occurrence in Zanardinula, but on 

 the other hand are equally if not more divergent from Grateloupia. The 

 description may be expanded as follows : 



Thalli 2-4 cm. high, densely branched and clumping in habit, rather 

 rigid, attached by a small disc, dark purplish red or greenish in color, 

 cartilaginous when dry; primary branching dichotomous, ± divaricate, 

 at intervals of 1-3 (4) mm.; secondary branching pinnate, irregular, 

 mostly in mid-parts of thalli, the pinnae usually determinate, 1-3 (4) 

 mm. long; segments compressed to flattened, 0.5-1.0 mm. wide, 280- 

 480 jx thick, appearing ± uniform in breadth throughout, the apices 

 usually as broad as lower parts, blunt, often somewhat swollen in fertile 

 plants; transection showing a dense medulla of interwoven, compacted 

 filaments, in younger stages showing numerous intercellular connections ; 

 cortex consisting of an outer region of anticlinal filaments of 5-6 small, 

 pigmented cells merging into 2-3 indefinite layers of larger cells with ± 

 prominent intercellular connections, these adjoining the medulla without 

 a distinct boundary; outer cortex in age amplified by secondary growth 

 of anticlinal filaments ; tetrasporangia borne in nemathecial sori covering 

 the short secondary pinnae and the terminal segments, slender, 40-50 ju, 

 long, 8-13 ju, broad ; cystocarps completely embedded in terminal segments 

 and in secondary pinnae, ostiolate, about 150 /a in diameter, the gonimo- 

 blast pedicellate from the auxiliary cell; antheridia borne in superficial 

 nemathecial sori covering terminal segments and secondary pinnae. 



Type: Holotype is Johnston 121, June 1922, on sheet 1369 in the 

 Herbarium of the California Academy of Sciences, San Francisco, 

 California. 



Type locality: Isla Tortuga, Gulf of California, Mexico. 



Mexican distribution: Sonora — D. 648-40, near Kino, July; 

 Marchant (in Herb. Calif. Acad. Sci.), Guaymas, May; D. 524, Bahia 

 Bocochibampo, near Guaymas, Feb. ; D. 723-40, Isla Turner, July. 

 Baja Calif, del Sur — D. 3451, Bahia de La Paz, Nov. 



