Notes on Mosses and Hepatics 493 



I will now mention a few of those mosses which may be 

 met with very commonly, and which are well worth careful 

 examination ; they do not require any preparatory treatment 

 before being examined. 



First the leaves. Most people know the bog mosses, 

 species of Sphagnum, which form patches of varying colours, 

 whitish-green or red, in moist woods and bogs ; the cells of 

 their leaves contain spiral filaments, and are most beautiful 

 objects for the microscope. The cell structure of many other 

 mosses is well worthy of examination ; for instance, there is a 

 moss which is often very common and of good size, covering 

 the ground in many places, Milium hprnum, the Swan's neck ; 

 the edges of the lanceolate leaves are thickened and denticu- 

 late, as are the others of the same genus, but the rest of the 

 leaf, with the exception of the nerve, is only one cell thick. 

 Many other more or less allied genera have the leaf uniform 

 without any thickening of the leaf. Pterygop hyllutn (Hookeria) 

 lucens, which is very local in the south of England, but not 

 very uncommon on shady banks by streams, is worthy of 

 mention on account of its very large leaf cells, which are 

 clearly distinguishable with a good pocket lens, looking like 

 a piece of fine muslin. Mnium and Bryum, various species 

 of which are common, afford good examples of wide, often 

 hexagonal, cells, while many of the larger mosses (Hypnum, 

 &c.) have the cells long and narrow. In some mosses the 

 cells near the base are very different from those in the rest of 

 the leaf. 



The peristomes of the capsules vary very much in form 

 and structure ; some have scarcely any visible peristome, 

 while others have a single row of teeth round the mouth of 

 the capsule, and others, again, a double row. The number 

 of these teeth is always a multiple of four :*4, 8, 16, 32, or 64. 

 Of those with single peristome, one which is sure to be met 

 with is Tortula muralis, the Wall Screw Moss, which grows 

 very abundantly on walls, stones, bricks, &c. ; the capsule is 

 subcylindrical and the red peristome teeth are long and 



