BRYOPHYTA 



A. MUSCI 



POLYTRICHUM COMMUNE, L. 



A. GENERAL EXTERNAL CHARACTERS 



I. Observe in well-grown specimens of this Moss taken in 

 spring or early summer 



1. The erect stem, 1 which may attain a considerable length, 

 branching but rarely : 



2. The leaves, 1 of relatively small size, and simple form ; 

 their arrangement is on a complicated plan : at the base of the 

 stem note 



3. A dense mat of rhizoids of brownish colour. 



At the apex of some specimens will be found merely a bud, 

 composed of young leaves of the vegetative type; other 

 specimens will bear at their apex 



4. Perieronia, or perichsetia ; cup-like rosettes of leaves, 

 which assume a bright reddish or orange colour, and protect 

 the antheridia; other specimens again may bear at their 

 apex 



5. The mature sporogonium or spore-capsule, of which the 



1 Though the terms "stem" and "leaf" are used here, it must be distinctly borne 

 in mind that the members thus named, being parts of the OOphyte generation 

 are not homologous with, but at most only analogous to the stem and leaf 

 of vascular plants, which are parts of the sporophy te generation. 



N 2 



