266 r>tivcrsity of California Publications in Botany [Vol.8 



•iO/A thick at about the middle and tlie cells in section are circular 

 or oblong and but very slightly elongated vertically in section even 

 when fertile. The substance of the membrane is soft and slightly 

 lubricous. Taken in this narrower sense, we find specimens both from 

 our own coasts and those of Europe in agreement. This leads us to 

 include this species as defined above, but not in the broad sense, as 

 including Ulva rigida Ag., TJ. latissim-a L., and other species as has 

 been the customary usage of recent writers. On this account, it is 

 impossible, at present, to give an extended synonymy under the 

 species. Vickei*s (1908, pi. 1) has figured what seems to be a tropical 

 form of true Viva Lactuca and Hauck has distributed a specimen from 

 Trieste (cf. Hauck and Kichter, Phj'k. Univ., no. 17). 



5. Ulva latissima L. 



Frond ample, broader than long, usually soon free and expanded, 

 often reaching a considerable size, yellowish green ; membrane 35-40/x 

 thick ; cells, in section, nearly square or elongated horizontally. 



On mud flats and in quiet bays sometimes completely covering 

 extensive areas. Alaska (Juneau). 



Linnaeus, Sp. Plant., vol. 2, 1753, p. 1163 (in part?). Ulva 

 Lactuca var. latissima De Candolle, Flore Francaise, ed. 3, vol. 2, 

 1805, p. 9; Collins, Green Alg. N. A., 1909, p. 215 (in part). Mar. 

 Alg. Vancouver Is., 1913, p. 103 (in part?) ; Setchell and Gardner, 

 Alg. N.W. Amer., 1903, p. 210 (in part). Ulva Lactuca myriotrema 

 Saunders, Alg. Harriman Exp., 1901, p. 410 (not of Le Jolis). 



Ulva latissima of the Species Plantarum (Linnaeus, 1753, p. 1163) 

 may or may not be the same as that of the Flora Suecica (Linnaeus, 

 1755, p. 433) and the questions as to whether either of these is the 

 U. latissima of other authors, whose conceptions also have varied, are 

 not to be solved by us. We infer that the specimen of Ulva latissima 

 in the Linnaean Herbarium is not labeled either in Linnaeus' own 

 hand or those of any known amanuensis (cf. Benjamin Daydon Jack- 

 son, 1912, p. 147). It is apparently (cf. Turner, Fuci, vol. 3, 1811, 

 p. 72 and English Botany, vol. 22, 1806, text under pi. 1551) a frag- 

 ment of the blade of Laminaria saccharina. The plant upon which the 

 name given in the Species Plantarum is based was collected by Lin- 

 naeus on his trip into West Gothland, Sweden (Linnaeus, 1753, p. 

 1163, "iter w. gotl. 160"). 



