264 A. W. Evmis — Arrangement of Genera of Sepaticce. 



Ptychanthus Nees, Hep. Eur. iii. p. 105: G. L. & N. Syu. Hep. p. 289; 

 Thysananthus Lindenb. in Syu. Hep. p. 286; 

 Bryopteris Liudenb. 1. c. p. 284. 



The genus Lejeunea is very widely distributed but is especially 

 abundant in tropical regions. As first published by Mademoiselle 

 Libert, it contained 2 species, — L. calcarea, and L. serpyllifolia of 

 Europe and America ; in its j)i'esent extended sense it is the largest 

 genus of Hepaticse, and contains 300 to 400 species. The genus is 

 divided by Spruce (Hep. Amaz. et And.) into 2 sections and 38 

 subgenera, as follows: — §1. Holostipae, comprising the subgenera 

 Stictolejeunea, Neurolejeunea, Peltolejetmea, Omjjhalolejeunea, Archi- 

 lejeunea, Ptychol&junea, Mastigolejeunea^ Thysanolejeunea, Dendrole- 

 jeiinea, Bryolejeimea, Acrolejeunea, Lopholejeunea, Platylejeunea, 

 Anojylolejeunea, Brachiolejeunea, Homalolejeunea, Dicranolejemiea 

 and Odontolejeunea. §2. Schizostipae comprising the subgenera 

 Prio7iolejeunea, Crossotolejeunea, Harpalejeun ea, Trachylejeunea, 

 Drepanolejeunea, Leptolejeunea, Ceratolejeunea, Taxilejeiinea, Ma- 

 crolejeunea, Otigoniolejeunea, Hygrolejeunea, Euosmolejeunea, Pyc- 

 nolejeunea, Potamolejeunea, Cheilolejetmea, Eulejeunea, Microle- 

 jeunea, Cololejeunea, DiplasioleJeiDiea and Colurolejeiinea. 



4. MyrioCOlea Spruce, Hep. Amaz. et Aud. p. 30.5 (1884). 



Contains a single species, 31. irrorata Spruce of South Ainerica. 



5. Radula Dum. Comm. bot. p. 112 (1822), in part. 

 Radula, sect. RadiUotypus Dum. Syll. Jung. p. 88 (1831). 



Radula Dum. Rev. des Genres, p. 14 (1835); Hep. Eur. p. 31 (1874): G. L. & N. 

 Syn. Hep. p. 253. 



CandoUea Raddi, Juno-. Etr. in Mem. Moden. xviii, p. 24 (1820), in part, not Can- 

 doUea Laljil. 



Martinellia S. F. Gray, Nat. Arr. Br. PI. i, p. 690 (1821), in part. 



A widely diffused genus of about 75 species, the typical one being 

 the common R. comjylanata Dum. The genera Rachda and Marti- 

 nellia, as first proposed by their authors, included the genera Padula, 

 Scapania and Plagiochila, as these are now understood. In his 

 Sylloge (pp. 37-43), Dumortier divided his original Radula into 

 three sections : — Radidotypus, Scapania and Plagiochila ; these he 

 soon elevated into the genera Radula, Scapania and Plagiochila 

 with almost their present limitations (Rev. des Genres, p. 14). If 

 we supersede any of Dumortier's names by the older Martinellia of 

 Gray, it should be Radida, since the first of Gray's species of Mar- 

 tinellia belong to that genu^. As, however, Gray's genus is so 

 loosely defined, and Dumortier's names are in so universal use, it is 



