26 . Vol. XLIII, Art. 1.— K. Yeiulo : 



those of the Metasoria, more or less narrowed apices with rough 



margins. 



Although the apical part of the sporophyll is variable in 

 appearance, as explained above, the basal part has a constant 

 character more or less specifically distinct. In some species the 

 base tapers gently into the petiole, and in others is cordate or 

 round with sharply defined petiole ; in some species it is asym- 

 metrical in a peculiar manner and in others always symmetrical. 

 By these characters of the sporophyll, together with its general 

 outline, we can often readily tell the species even in a specimen 

 with the whole part of the blade withered away. 



b) Disposition of sporophylls on the stipe. The various modes 

 of disposition of sporophylls are expressed by the terms pinnate, 

 distantly pinnate, fasciculate, etc., which shall be used and regard- 

 ed with utmost care. Early European botanists to whom only A. 

 escidenta has been the familiar species, were rather careless in 

 describing the character. 



EosENVENGE^) and JÖNssoN^) are of the opinion that the posi- 

 tion of the sporophylls is not of any systematic importance. As 

 has been already stated, the early-formed sporophylls are disposed 

 on the stipe at much wider intervals than the later-formed ones. 

 It is therefore apparently right to agree with these two botanists, 

 when we compare different-aged plants of one and the same 

 species. But when fully matured plants of the different true species 

 have been laid before us we can make out in each a more or less 

 constant character in the disposition of the sporophylls. 



Alaria esculent a Geev., the type of the genus, has the sporo- 

 phylls arranged regularly pinnate, with nearly constant intervals 



1) Rosentenge: Gröolands Havalger, p. 839. 



2) JoNssoN : Mar. Alg. East Greenland, p. 23. 



