OF ARTS AND SCIENCES. 



211 



I can ju<l;j:e, epseniially the same in the two specie3. S. bulhosa, too, 

 is the only other alga, as far as is known, that possesses the peculiar 

 sclerenehyma fibres. Furthermore, S, bulbosn has paraphyses of the 

 same peculiar kind with S. dermatodea. Both are annual plants, 

 while the majority of the Laminariece are perennials. These two 

 species seem to constitute a distinct and natural genus, in which are 

 also placed several smaller European species of more or less doubtful 

 autonomy. Saccorkiza, proposed by De la Pylaie m 1829,* has the 

 right of priority. H<dt(je)iin, proposed by Decaisne in 1842, f included 

 »S^. bulbosa only. It was extended in 1856 by Le Jolis t to include 

 .S*. dermatodea. Le Jolis divided Haligenia into two sections : Sacco- 

 rkiza, to include S. bulbosa, etc., and Phyllaria, to include S. der- 

 matodea and others. Phyllaria has since been used by Gobi § and 

 Kjellman || as an independent genus. Kutzing made S. bulbosa the 

 type of the genus Phycocastamim in 1843.1[ There seems to be no 

 need of separating the two species, and consequently they should both 

 be included under the older name of SaccorJdza. 



Relation to the other Laminariece. — The relation of these two 

 species to the rest of the species of the Laminariece is at once complex 

 and interesting. The first organ that suggests itself as important in 

 this discussion is the holdfast. Chorda has in all probability the 

 simplest holdfast of any member of the group. The holdfast in this 

 genus appears to be merely the primitive disk expanded. Nothing 

 like hapteres is produced. Laminaria solidungida seems to repro- 

 duce the holdfast of Chorda, but on a larger scale. Next comes 

 Saccorhiza dermatodea, in which the primitive disk does not produce 

 hapteres, and where only two successive whorls of hapteres are pro- 

 duced from the rhizogen. Saccorhiza bulbosa differs not only in 

 producing a greater number of whorls of hapteres from the rhizogen, 

 and the consequent enlargement of that organ, but also in producing 

 hapteres from the primitive disk as well.** 



In the rest of the Laminariece the holdfast is more complex. In 

 most cases the hapteres are numerous and branched, and it seems a 

 difficult task to bring them into homology with these simpler forms. 

 But they may be separated into two classes : Jirst, those with hapteres 



* Fl. Terre Neuve, p. 23. 

 t Ann. Sci. Nat., Ser. 2, Tom. XVII. p. 330. 

 t Examen I., p. 591. 

 § Alg-Fl. Weiss. Meeres, p. 75, 1878. 



II Arct. Alg., p. 223. 1 Phyc. Gen., p. 346. 



** Cf. Barber, Annals of Botany, Vol III. p. 46, PI. V Figs. 1, 2, 3, and 6. 



