180 THE CLASSIFICATION OF THE TILOPTERIDACE^. 



and it is not desirable to rely to too great an extent upon 

 habit as a diagnostic character unless accompanied by 

 demonstrable differences in histological structure. 



From what has been said above, it is obvious that Hap- 

 lospora and Scapliospora can no longer be regarded as 

 separate and independent genera, and the question arises 

 which of the two, if either, is to be retained. This should 

 present no difficulty, since the genus Haplospora was 

 established by Kjellman^ five years before Scaphospora,^ 

 and therefore, by the accepted laws of nomenclature, 

 must be retained on the mere ground of priority of descrip- 

 tion. Kjellman had already described Scapliospora speciosa 

 under the name Capsicarpella speciosa at the time he 

 made the new genus Haplospoi^a^ but placed it among the 

 Ectocarpacece. He subsequently, however, rejected the 

 generic name Capsicarpella (Bory) Kjellm. in favour of 

 Scapliospora, at the same time placing the alga among 

 the Tilopteridacese, and this latter genus has since been 

 generally accepted. Eeinke^ suggests that both Haplo- 

 spora and Scapliospora should be merged in Tilopteris, 

 but it seems hardly desirable to adopt this course, for Haj^- 

 lospora has long been established, and almost universall}' 

 accepted as valid by algolgists of all shades of opinion. 

 Moreover, there are valid reasons for regarding it as an 

 independent genus. The real difference between the genera 

 Tilopteris and Haplospora seems to lie in the fact that in 

 the former the sporangia and (presumed) oogonia are similar 

 in form, and occupy a similar position in the frond, while 

 in Haplosp>ora (Kjellm.) limit, mutat., the oogonia and 

 sporangia are dissimilar in form, and normally occupy 

 different positions in the frond. One of Reinke's reasons 

 for considering that Scapliospora Kjellm. and Haplospora 



1 I.e. 2 I.e., p. 29. 3 i,c, Sejx Abdr., p. 17. 



