92 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



LAMINARIA, Lainx.— BeviVs Aprons; 



(From lamina, a plate. ) 



Fronds attached by a branching base,* stipitate, stipe expanding into 

 a ribless entire or laciniate lamina ; fruit forming bands or sori in the 

 central part of the lamina, consisting of unicellular paraphyses and uni- 

 locular sporangia densely packed together ; cryptostomata wanting. 



A genus comprising not far from twenty-five species, which inhabit principally seas 

 in high latitudes. They all grow in pools at low- water mark and in deep water, and 

 some attain a very large size. The limits of the genus are well fixed, hut the same 

 can by no means be said of the species, with regard to which writers differ very 

 much. The difficulty arises partly from the fact that the species lose some of their 

 characteristic marks in drying, so that the study of herbarium specimens is unsatis- 

 factory, but still more from the fact that the species vary greatly iu outline and habit 

 according to the season and the place of growth, whether at an exposed or sheltered 

 coast or whether submerged or partly exposed at low tide. In general, the species 

 may be classed in two groups, those in which the frond is ribbon-like, that is, long in 

 proportion to the breadth and not split up into segments, and those in which the frond 

 is proportionately broader and fan-shaped and, except when young, laciniate. To the 

 former group belongs the L. saccharina of older writers, to the latter L. digitata, and 

 it is with regard to the extent to which subdivision shall be carried in the two cases 

 mentioned that recent writers differ very widely. Our species have not been suffi- 

 ciectly studied in situ to warrant us in giving the determinations with any degree of 

 confidence. More information with regard to their winter condition is very much 

 needed. The most detailed account of the Laminarice of the eastern coast is to be 

 found in the paper of De la Pylaie in the Annales des Sciences Naturelles, Ser. 1, 

 Vol. IV", 1824, entitled " Quelques observations sur les productions de File de Terre- 

 Npuve, et sur quelques algues de la cote de France appartenant au genre Laminaire." 

 The article is accompanied by a plate in which is sufficiently well shown the habit of 

 our common species. The same writer in 1829 gave a more extended account of his 

 collections in the "Flore de Terre-Neuve et des lies Saint Pierre et Miclon," an incom- 

 plete work comprehending the Laminariacem and Fucacece, of which, however, the plates 

 were never published. The species of De la Pylaie have not been accepted without 

 question by algologists, and all agree that he was too liberal in the formation of new 

 species. Harvey ignores the greater part of them in the Nereis. Agardh and Le Jolis 

 give them a more respectful consideration, and the former especially is inclined, in his 

 paper on the Laminariacece and Fucacece of Greenland, to admit several of De la Pylaie's 

 species. In the present case we do not feel at liberty to make use of the notes with 

 regard to American forms which have been kindly furnished by European correspond- 

 ents, but must content ourselves with a superficial account of the perplexing forms of 

 this exasperating genus, adding that the identity of our forms with those of Europe is 

 not in all cases proved. 



Of the species of Laminaria given in the Nereis, L. fascia in now placed in Phyllitis ; 

 L. lorea and L. dermatodea refer to the same plant, which is now placed in Saccorhiza ; 

 L. longicruris is still kept as in the Nereis ; L. saccharina and L. digitata are kept with 

 limitations ; and L. trilaminata is, as Harvey suspected, merely an abnormal winged 

 form of some other species, corresponding to the trilaminate condition mentioned under 

 Agarum Turneri. 



The marks used in distinguishing the species are the arrangment of the root-fibers ; 

 the structure of the stipe, whether solid or hollow, whether provided with distinct 

 cavities containing mucus (muciparous glands) the shape of the lamina, more particu- 



* A few species, asi. solidungula, Ag., have a disk-like base, and L. sessilis, Ag., in- 

 cluding L. apoda, Harv., found on our west coast, has no stipe properly speaking. 



