IN BRYOLOGICAL WORK. 533 



Notes on a Collection of Slides of Mosses. 



Polytrichum formosum. 



Sections of a leaf cut to show the jointed appendages that 

 constitute the lamellae. These appendages are of great use in 

 determining the species, as the form of the terminal cell, the 

 number of cells in each appendage, and the average number of 

 appendages in the transverse section differ with the species. 



Ceratodon purpureus 



A common moss in dry woods, on sandy banks, etc., but also 

 a very polymorphous moss. In spite of considerable leaf 

 variation, however, a distinct and constant feature is the 

 recurved margin, becoming plane immediately below the apex, 

 which is usually toothed. The characteristic annulus is well 

 shown in the slide. 



Dicranum majus. 



A fine moss usually occurring in mountainous woods. The 

 common and variable Dicranum scoparium in some of its forms, 

 which are chiefly barren, approaches it very closely. Dicranum 

 majus, however, bears a multiple number (2-5) of setae from 

 one perichaetium. Both species belong to the section Eu- 

 Dicranum, which is characterised by the leaves having lateral 

 pores connecting the cells in the lower part of the leaf. 



Leucobryum glaucum. 



An interesting moss, the leaves of which are well worth 

 careful examination. The chlorophyll cells are masked by an 

 outer layer of hyaline, inflated corky cells communicating by 

 pores. The greater portion of the leaf is composed of the nerve. 

 Cardot has monographed the genus, see his Recherches Anatomiques 

 sur les Leucobryacees. It is a not uncommon moss on dry, turfy 

 ground, but the fruit is very rare, and according to my experience 

 found chiefly when the moss grows in quite damp localities. A 

 curious state of the moss occurs in dry woods in which it forms 

 small rounded cushions, quite detached from the ground, and 



