BRYOPPIYTA 349 



Order Anthocbrotalbs. Hornworts. Sporophyte elon- 

 gated, with a columella and elaters, 

 two-valved. 



Family 2. Anthocerotaceae. Gametophyte a flat 

 thallus. — Anthoceros. 

 Order IMabchantiales. Great Liverworts. Sporophyte 

 rounded, without columella, indehis- 

 cent. 



Family 3. Corsiniaceae. 



Family 4. Marchantiaceae. Gametophyte large, 

 thallose, branching, with elaters. — 

 Marchantia, Conocephalus. 

 Order Jungebmanniales. Scale Mosses. Sporophyte 

 stalked, four-valved; with elaters. 



Family 6. 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 Andbeaeales. 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 Beyales. True Mosses. Sporophytes mostly long- 

 stalked, generally opening by a circu- 

 lar lid, usually with a peristome. 

 Sub-order Aceocabpi. "Top Mosses." Sporophytes 

 terminal on the main axis of the 

 gametophyte. 



Family 9. Archidiaceae; 10, Dicranaceae ("Turf 

 Mosses"); 11, Leucobryaceae (" Gush- 



