ESSAY 



OF A NATURAL CLASSIFICATION OF THE LICMOPHORAE 



The genus Licmophora from a comparatively small one, as it has 

 been heretofore, having now grown up lo a large one, it has hecome 

 neccssary to distrihute the numerous species and varieties in natu- 

 rai groupes according to their aijinities. The system of Grunow ba- 

 sed on a single character — the depth of the septa is by this vcry 

 reason an artificial one, and in fact both of bis groupes, the Subse- 

 ptatae and Profundeseptatae contain the most heterogeneous forms, 

 and at the same time separate species, which are closely allied, as 

 for instance L. Ehrenbergìì from L. Gruìiowìi, or L. dahnatìca from 

 L. paradoxa. A naturai system must take in consideration not one 

 characteristic only, but ali of the chracteristics. 



In my Monography, if 1 ever succeed to publish it, l will deal 

 with this question more in detail, at the present time I will only 

 give a short characteristic of the difterent groupes which can be esta- 

 blished with a list of species belonging to each of them. 



I. Placatae. — Valve narrow, striae very line, sepia quite super- 

 Jicìaì, frustale delicate, endoclirome composcd of 2-^ plates, stipes struc- 

 turless (compound and striate in /.. Jìaì'elhila). 



1. L. bìplacaia Mer. 



2. L. qiiadripìacata Mer. 



3. L. flabellata (Carmichael) C. y\gardh. 



4. — var. parva Mer. 



II. Dublae. — Valve usually more or less bacilliform, slightiy at- 

 tenuated from the very summit which is broadly rounded, striae very 



