BRYOPHYTA 349 



Order ANTHOCEROTALES. Hornworts. Sporophyte elon- 

 gated, with a columella and elate rs, 

 two-valved. 



Family 2. Anthocerotaceae. Gametophyte a flat 



thallus. Anthoceros. 



Order MARCHANTIALES. Great Liverworts. Sporophyte 

 rounded, without columella, indehis- 

 cent. 



Family 3. Gorsiniaceae. 



Family 4. Marchantiaceae. Gametophyte large, 

 thallose, branching, with elaters. 

 Marchantia, Conocephalus. 



Order JUNGERMANNIALES. Scale Mosses. Sporophyte 

 stalked, four-valved; with elaters. 



Family 5. Metzgeriaceae. Gametophyte usually 

 thallose, archegones lateral. Metz- 

 geria, Pellia, Fossombronia. 



Family 6. Jungermanniaceae. Gametophyte a bi- 

 lateral leafy stem, archegones termi- 

 nal. Lophosia, Bazzania, Scapania, 

 Frullania. 



Class 19. MUSCI. Mosses. Gametophytes multilateral, usu- 

 ally erect; sporophytes mostly dehis- 

 cent by a circular lid, and without 

 elaters. (Sp. about 12,600.) 



Order ANDREAEALES. Black Mosses. Sporophyte short- 

 stalked, opening by four to six longi- 

 tudinal slits. 



Family 7. Andreaeaceae. Small mosses. Andreaea. 

 Order SPHAGNALES. Peat Mosses. Sporophyte short- 

 stalked, opening by a circular lid. 



Family 8. Sphagnaceae. Large bog mosses. Sphag- 

 num. 



Order BRYALES. True Mosses. Sporophytes mostly long- 

 stalked, generally opening by a circu- 

 lar lid, usually with a peristome. 



Sub-order ACROCARPI. "Top Mosses." Sporophytes 

 terminal on the main axis of the 

 gametophyte. 



Family 9. Archidiaceae; 10, Dicranaceae ("Turf 

 Mosses"); 11, Leucobryaceae (" Gush- 



