284 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



Fronds to 7 cm. high, rigid, cartilaginous, attached to rocks by a small 

 disk from which one or a few main axes arise, compressed, 1.5-2 mm. 

 broad, occasionally forked, with many pinnate branches; pinnae com- 

 monly standing at right angles to the main axis, often arising very close 

 together, narrowed to the point of attachment, broadest beyond the 

 middle, .7-1.0 mm., of varying length 5-18 mm., occasionally forked or 

 branched; apices semiacute, not attenuated; reproduction unknown. 



Type: D. & R. 3402 (Field Museum; isotype AHF no. 32), in 

 intertidal rock pools, Punta San Pedro, near Guaymas, Dec. 22, 1939. 



D. 46, on rocks near wharf, Guaymas Harbor, Jan., 1940; D. 295, 

 on middle littoral rocks, Puerto Refugio, Jan., 1940. 



This species resembles Prionitis abbreviata and P. Sternbergii m some 

 respects, but the narrow fronds and peculiar long-pinnate branching mark 

 it as distinct. No other Pacific species resembles this plant sufficiently to 

 be much confused with it. 



Prionitis kinoensis sp. nov. 

 Plate 67, Fig. 1 



Frondes caespitosae, 2.4 cm, altis, stipitibus curtis, atro-purpureae, copiose 

 dichotomae, segmentis compressis, plerumque 0.6-0.8 mm. latis, internodiis infernis 

 longioribus et frequenter dense pinnatis; ramellorum externorum pinnis egentibus; 

 structura generis typica. 



Plants caespitose, a clump 5-6 cm. diam. from a single, short stipe (.5 

 cm.) attached to rock surfaces, 2-4 cm. high; dark purplish in color; 

 fronds abundantly dichotomous, especially above, the segments com- 

 pressed, mostly .6-. 8 mm. broad, the lower internodes longer and fre- 

 quently close-pinnate ; pinnae absent from outer branches ; structure typi- 

 cal of Prionitis; apices blunt; reproduction unknown; texture slippery 

 when fresh. 



Type: D. 648, middle littoral rocks, rocky point 3 miles north of 

 Kino, July 16, 1940. Herb. AHF no. 33. 



D. 723, lower littoral rocks. Turner's Island reef, July 18, 1940. 



This is the smallest and one of the most distinctive members of the 

 genus on the Pacific coasts of North America. The thickly caespitose habit 

 and abundant dichotomies of the narrow branches are distinctive. The 

 pinnate character of the genus is also exhibited on the lower segments, 

 making easier the identification of the genus of this plant, which is so 

 different in size and form from most of the others of our coast. It is 

 probably another summer annual, not having been found at Turner's 

 Island in January. 



