206 THE MOSSES OF ESSEX : 



pvriformis, a common moss of the peaty soil of heaths in the 

 county, usually found in tufts covered with the broken leaves. 



No species of moss is restricted in its British distribution to 

 Essex, although until recently Zygodon forsteri had been found 

 only in this county, at first on a felled tree in Walthamstow at 

 the beginning of the last century ; later, on beeches in at least 

 two localities in Epping Forest. It has now been found in two 

 other English counties. It is curious that wherever this moss 

 occurs it is always found in a very scattered fashion, both in this 

 country and on the continent. One would scarcely look for 

 such an alpine species as Gvimmia commutata in Essex, but Mr. 

 H. N. Dixon found it growing on the roof of a house at Wickham 

 Bishops ; perhaps other alpine species may be discovered 

 occasionally in a similar fashion if search is made for them. It 

 was suggested that possibly the spores had been carried by the 

 wind across the North Sea from the mountains of Norway, 

 where the moss is common. 



Among species of which there is at present no record for the 

 county, but which should be found here, may be mentioned 

 Polytrichum urnigerum, P. gracile, Seligevia paucifolia, Ditviclium 

 schreberi, Leptodontium flexifolium, Encalypta stveptocavpa, Br yum 

 pendulum, B. donianum, Milium stellar e t Hypnum polygamum, and 

 H. lycopodioides. 



Not only is there much to be done in Essex as far as mere 

 species recording goes, but anyone taking up the study of the 

 mosses will find them of much interest in themselves. YVe have 

 to deal with a series of plants in which the gametophyte genera- 

 tion has reached the fullest development forming the leafy plant, 

 while in all other plants the leafy plant belongs to the sporophyte 

 generation with the sole exception of the nearly allied Hepaticae. 

 The Musci have followed a line of development of their own, and 

 it has come to an end with the more elaborate of their forms. 

 The manner of obtaining w-ater is full of interest and varies 

 greatly in the different species, affording matter for much study ; 

 the form and papillosity of the leaves, the arrangements of 

 lamellae on the leaf surface, the presence of hair points, etc., are 

 all matters apparently closely connected with the obtaining of an 

 adequate supply of water. The part they play in the economy 

 of Nature, the relation they bear to other forms of life, particularly 

 as formers of soil, and lastly, a subject about which we probably 



