NO. 1 TAYLOR: PACIFIC MARINE ALGAE 291 



in transverse section showing the surface cortical cells not swollen, 

 rounded angular, to about 30 fi, diam. and about as deep, not appearing 

 different from the outer medullaiy cells; medulla about 8-10 cells in 

 radial dimension, the inner progressively much larger, but the pericentral 

 cells hardly distinguishable; axes at the base somewhat denuded but for 

 the most part very closely alternately radially beset with short determi- 

 nate lateral ascending often curved branchlets which reach a length of 

 1-2 mm, are simple or more often alternately closely branched with 2-5 

 divisions; smaller branchlets or divisions turbinate, the expanded ends 

 somewhat depressed, the bases hardly contracted, later somewhat lobed 

 and eventually developing branchlets; older branchlets more nearly 

 cylindrical, diameter to 0.40-0.55 mm; tetrasporangia near the ends of 

 the branchlets, to 75 ft diam. 



As with most small Laurencias, Chondrias, and Hypneas, the descrip- 

 tion of miniature species is dangerous except after prolonged field study, 

 because the chances are so great that the plants are dwarf forms of larger 

 species. The writer is familiar in the Caribbean with turflike forms of 

 Laurencia obtusa, L. intricata, and L. papulosa, for example, where the 

 individuals over large areas show little resemblance to their well-devel- 

 oped relatives, but where in a slightly sheltered nook of the same terrain 

 all transitions establishing the relationship may be readily secured. How- 

 ever, in this instance the plants are ecologically important and nothing 

 known to the writer in the flora of the area is entirely satisfactoiy as a 

 larger-scale relative from which these plants could have been derived. 

 The most plausible is L. obtusiuscula Setchell & Gardner ( 1924, p. 760) 

 and especially the var. corymbifera Setchell & Gardner (1924, p. 761), 

 but in ours the branches are more turbinate and more densely placed, but 

 not verticillate. 



Mexico: Guerrero, forming turfs near low tide line in the severe 

 surf of White Friars Is., no. 39-628 (tetrasporic, TYPE), 9 May 1939. 



Laurencia peninsularis n. sp.^^* 

 Plate 98, Fig. 1 



Plants bushy, about 2 dm tall, dull red, soft and adhering to paper 

 when mounted, the elongated main axes sparingly branched, definitely 

 percurrent, bearing at intervals of 5-10 mm short lateral branches, gen- 



184 Laurencia peninsularis n. sp.— Plantae ad 2 dm altitudine, fruticosae, axibus 

 priraariis sparse ramosis, percurrentibus, ferentibus, in intervallis 5-10 mm, ramos 

 laterales breves 1-2 cm long, qui ramulos alternos, cylindricos ad subclayatos, 0.3- 

 0.5 mm diam., 1-3 alterne furcatos proferunt. Planta typica in loco dicto Point 

 Hughes, Baja California, Mexico, legit W. R. Taylor no. 3-i-607, 7 Mar. 1934. 



