Heath Association on Hindhead Common. 155 
that the water-content of the soil is appreciably less on the top of 
the ridge than on the sides of the slopes and in the valleys, and it 
is possible that this factor determines the distribution of the two 
important grasses, although we should not like to accept such a 
conclusion without further evidence. It will be well at this point 
to refer to the distribution of another member of the heath- 
vegetation. In the heaths of other parts of England Erica Tetralix 
appears to favour the damper places. We can find no evidence of 
this on the heath at Hindhead, for this species shows no special 
restriction to certain points, and is, if anything, most abundant on 
the relatively dry summit of the ridge. 1 
There is no difference in specific constitution between the 
different facies of the Callunetum on the Hindhead heath, but, as 
the above description will have shown, the relative grouping of the 
species varies. The following is a complete list of the members of 
the Callunetum , found on the area at present mapped:— 
Calluna vulea ris 
o 
Erica cinerea 
„ Tetralix 
Vaccinium Myrtillus 
Ulex europceus (only isolated 
patches) 
„ minor 
Potentilla erecta (isolated) 
Cuscuta E pithy mum (rare, cf. p. 159) 
Agrostis canina (rare) 
Deschampsia flexuosa 
Molinia coerulea 
Triodia decumbens (rare) 
Rhamnus Frangula 
Betula alba 
Cratcegus monogyna (rare) 
Pyrus Aucuparia 
„ Aria 
Ilex Aquifolium 
Pinus sylvestris 
Pteridium aquilinum 
Blechnum Spicant (rare) 
Along the edges of and in the immediate neighbourhood of the 
pathways a much larger number of species are found. Some of 
these are “ weeds ” but many are characteristic of southern Calluna- 
heaths 2 or of grass-heaths 3 , but on the Hindhead Common are 
either strictly confined to the paths or only penetrate into the 
heath proper for a distance of 20-30 feet at the utmost from the 
paths. The following is a list of these species:— 
1 On the part of Frensham Common lying in the neighbourhood of the 
Little Pond, however, Erica Tetralix shows a decided preference for the damper 
ground. The heath on this part of the common consists of practically nothing 
but low Calliuia (about 1 foot high) with an almost complete covering of Cladonia 
on the soil. In the neighbourhood of the water, however, Erica Tetralix appears 
in abundance, at some points even extending right into the marsh bounding 
the pond. 
2 cf. Tansley, Types, p. 105. 
3 Tansley, pp. 95, 96. 
