222 MOSSES. CHAP. II. 



thinks they may, perhaps, serve in either case the 

 purpose of calyx, or of corolla, or of both.* 



Sheath. But however this may be, the parts of the flower 

 soon begin to assume a different appearance, as the 

 process of fructification advances, the fine and 

 pointed substances expanding into a sort of length- 

 ened cone, invested by a thin and membranaceous 

 integument, which is adherent at the base and 

 summit, but inflated towards the middle, and 

 which finally separates horizontally into two dis- 

 tinct portions. The under portion, which is placed 

 within the perichsetium, remains, as before, attached 

 to the base of the fructification, and is designated 

 by the name of the sheath ; while the upper por- 

 tion adheres also, as before, to the summit of the 

 fructification, which it still partially invests in the 

 form of an extinguisher. In this stage it has been 

 called by some botanists a calyx, and by others a 

 corolla.^ But its resemblance to either is so ex- 

 tremely slight, as scarcely to justify the application 

 of the term. It is more generally known, however, 



Calyptra. by the appellation of the calyptra or veil, a term 

 sufficiently expressive of at least part of its func- 

 tions, masking as it does, a globular or urn-shaped 

 vessel, which is the capsule of the Mosses. In 



Capsule, some species this capsule is sessile, or very nearly 



so, as in Phascum muticum ; but in by far the 



greatest number it is elevated upon a fine and often 



capillary but conspicuous pedicle, as in Polytrichum 



* Introd. p. 4Sp. f Fund. Hist. Nat. Mus. chap. x. 



6 



