1920 Pease; on Desmarestia 323 



opposite branches which break up into fine veinlets. The species name 

 is given on account of the resemblance of the simple frond to a long 

 narrow pinnately veined leaiV 



Type specimens are deposited in the Alga Herbarium of the Uni- 

 versity of Minnesota. 



In a preliminary paper the writer (Pease, 1917) described and 

 figured a series of plants collected during the summer of 1916, which she 

 referred to D. tahacoides, first described by Okamura (1908) from 

 material collected in southern Japan. Okamura describes his new species 

 thus: "Fronds very large, leaf-like, shortly stipitate, with broadly oval, 

 very usually obliquely lobed, simple, midribbed, and coriaceous lamina. 

 The midrib is slightly prominent below, but gradually becoming fainter 

 upwards, with opposite veins which dissolve, even from the base, into 



numerous fine veinlets The outline of lamina is of large oval 



shape with the length of 30-70 cm. and breadth of 20-50 cm." The 



description is accompanied by an excellent plate. Since publishing the 

 article referred to, the writer has had the privilege, through the kindness 

 of Dr. W. A. Setchell of the University of California, of examining an 

 authentic herbarium specimen of Okamura's plant. She detects the fol- 

 lowing differences: 1. The oblique lobing which Okamura mentions in 

 his description. Plants collected on the American coast have sinuate 

 margins with obscure teeth rather widely separated, while the Japanese 

 specimens were "very usually obliquely lobed." 2. The opposite veins, 

 "which dissolve even from the base, into numerous fine veinlets." These 

 are close together, and all their branches come oif at very acute angles, 

 corresponding to the "erect branching" of some of the filiform species, 

 and take the same general direction toward the margin of the frond; 

 while in American material the secondary branches are given off more 

 nearly at right angles and have a more definitely reticulate appearance. 

 The distance between the pairs of opposite veins seems to vary with the 

 size, and hence the age, of the specimen. 3. The stipe seems to be much 

 more slender in American specimens. 4. The frond, which in Japanese 

 material is of a large oval shape and reaches a breadth of 20-50 cm., is 

 long and strap-like in American specimens, and not over 15 cm. wide, 

 so far as known. 



The dcscri]ition of D. pinvaiinervm given by De Toni (1895) applied 

 so well to both Japanese and American specimens that the earlier literature 

 was consulted. D. pinnatinervia was first described by Montagne (1842) 

 with the comment, "a single specimen collected in 1 823 on the coast of 

 Spain, in the harbor of San Sebastian and for a long time considered as a 

 Laminaria." He describes the new species as follows: "Frond stipitata 

 tenuissime membranacea marline denticulis distantibus instructa nervo 



