82 
W. Watson. 
conditions most of the interlinking furrows have a thin basal layer 
of water, the depth varying according to fluctuating conditions and 
undulations of the ground. 
Fig. 2. Sketch-chart of a portion of the heath showing the distribution 
of the bryophytic zones. The double lines enclose channels of open water 
during moist weather conditions. Scale 1 in 50. 
The lower and flatter portion of the field is less definitely 
mapped out into intersected areas (Pig. 1), is often swampy and 
local societies of Hypericum elodes, Menyanthes trifoliata, Mnium 
affine (the form often known as var. elatmn), and Bryum pseudo¬ 
triquetrum may occur in a matrix of Hypnum cuspidatum, H. 
stellatum, H. intermedium, H. giganteum and Sphagnum spp., with 
an abundance of Hydrocotyle vulgaris , Galium uliginosum and 
Anagallis tenella . 
The surrounding fields have been drained and are used for 
pasture, except on one side where the triangular apex of a dry heath 
almost abuts on the wet heath (Fig. 1). On this dry heath gorse 
