S24 Pub. Puget Sound Biol. Sta. Vol. 2, No. 53 



pertenui longitudinal! aliisque transversis oppositis parallelis percursa." 

 The characteristics which finally decided him to remove the plant from 

 the genus Laminaria and consider it as the type specimen of a new 

 species of Desmarestia were the presence of: 1, a definite stipe; 2, a median 

 vein which extends throughout the length of the frond and gives off op- 

 posite lateral branches. The colored plate which accompanies the de- 

 scription shows the same general growth habit as the Japanese and Amer- 

 ican specimens, i. e., a broad, flat frond, unbranched, with a median vein 

 which gives off opposite lateral branches, the latter branching again. It 

 does not, however, give the details of the venation, only one secondary 

 branch from each lateral vein being shown. 



Agardh (1848), who according to Montague, had examined the orig- 

 inal specimen, lists it under "Species inquirendae" with the remark, 

 "Videtur pars inferior frondis latioris Desmarestiae ligulaitae." His 

 description, "Fronde latissima plana costate simplice, margine edentato 

 serrata, in stipitem attenuata," varies somewhat from Mantagne's and may 

 have been either from the specimen itself or from Mantagne's plate. 



Kiitzing (1849) must have written his description from the plate, as 

 the phrase "costis apice bifurcatis" would indicate, the plate showing only 

 one secondary branch from each lateral vein and no finer subdivisions. 

 De Toni (1895) quotes Kiitzing's description, adding Agardh's comment 

 concerning its resemblance to "D. ligulata var. firma." 



Johnstone and Croall (1859) close their discussion of D. ligulata by 

 saying, "Under the present species we would place the form D. pinnati- 

 nervia, our impression being that they are identical; although at first sight 

 the great breath of the frond, and the very narrow and distinct pinnated 

 nerve, would indicate a distinct species." Although claiming to have 

 specimens collected in the north of Ireland, they give no plate, and the 

 species is' not mentioned by other writers in lists of British marine algae. 



It would seem then, that all authentic published accounts of this 

 species are based on Montagne's and Agardh's opinions of a single speci- 

 men, Kiitzing apparently having written his description from Montagne's 

 plate and De Toni having quoted Kiitzing and Agardh. 



Until specimens of the three can be placed side by side for comparison, 

 the most that can be said is that the Japanese, the American, and the 

 Spanish plants resemble each other very closely, and if not three very 

 closely related species, -^e three forms of the same species. 



The ligulate specie» wf the genus Desmarestia should be further sub- 

 divided, then, into two groups, one to include the branched forms, the otlier 

 the simple forms. It was this unbranched condition of the frond which 

 caused Montague to hesitate for nearly 20 years before finally classifying 



