T. Holm — Studies in the Cyperacece. 435 



Akt. XLYIII. — Studies in the Cyperacece ; by Theo. Holm. 

 X. Fimbristylis Vahl ; an anatomical treatise of North 

 American species. With fourteen figures in text, drawn 

 from nature by the author. 



That purely floral characters are insufficient for the estab- 

 lishment of genera has been proved by several botanists in 

 recent years. This is especially the case with large orders, 

 where a number of species are to be classified so as to demon- 

 strate, at least, a supposed relationship. It is not uncommon 

 that herbalists content themselves by studying only the floral 

 structure and matching the details with some old illustration 

 or analytical key ; but there is, however, more than that to be 

 considered and looked upon, as affinity and relationship. The 

 establishment of natural orders is, of course, a progress, but, to 

 say the least, the genera themselves are often so badly under- 

 stood and so arranged, that we obtain no more knowledge of 

 the real affinities than if we had followed the system of Lin- 

 naeus : Monandria, Diandria and so on. It is very common to 

 see species arranged in genera widely apart, on account of the 

 stamens and stigmata being different in number, while the 

 plants otherwise show the same habits and internal structure. 

 Our genus Fimbristylis furnishes a good illustration. Merely 

 because some species have two or three stigmata, this genus has 

 been divided into Dichelostylis and Trichelostylis ; and the 

 fact that the base of the style is persistent in some species, but 

 only for some time, has caused the separation of the genera 

 Isolepis and Oncostylis* Furthermore these genera have 

 been considered as subgenera of Scirpus or even as close allies 

 of Heleocharis, a consideration, however, that cannot possibly 

 have been based upon observations in the field. But to 

 Bentham and Asa Gray such characters were of less importance, 

 and these authors were liberal enough to include a number of 

 species as true Fimbristyles, even if the floral characters did 

 not come exactly within the scope of the original diagnosis or 

 conception of the genus as understood by Yahl. Finally the 

 anatomical study of a number of genera of the Cyperacece has 

 shown us that certain analogies exist which must be con- 

 sidered as valuable to the study of mutual affinities, promul- 

 gated by Schwendener, Pallaf and Rikli. 



* It was Martius (Flor. Brasil.) who substituted the generic name Oncostylis for 

 Bulbostylis, which appears in the Conspectus generum, because DeCandolle had 

 already used Bulbostylis to designate a genus of Compositce. 



f Palla Ed. Zur Kenntniss der G-attung " Scirpus." (Engler's botan. Jahr- 

 bucher, vol. x, Leipzig, 1889, p. 293.) 



Am. Jour. Sci.— Fourth Series, Vol. VII, No. 42.— June, 1899. 

 29 



