Further Observations on Heath Association. 137 
Spontaneous colonisation, mainly by Pinus and Betula, is a 
prominent feature, but owing to the felling of these over the greater 
part of the heath, on reaching a certain size, they fail to lead to a 
further phase. At the south end of the common however, such 
colonisation has not been interfered with, so that a definite wood¬ 
land (in which Pinus sylvestris predominates) has been established; 
reference to the survey-map of 1895 shows no indication of wood¬ 
land here at that time. That the Hindhead Common may formerly 
have been occupied by woodland is suggested by the abundance of 
woodland plants ( Anemone nemorosa, Viola riviniana, Orchis 
inaculata, etc.) in the valleys. 
In conclusion we may call attention to the close resemblance, 
both as to the successive phases and final condition, which the flora 
of this southern heath bears to the “ thin moors ” of North-East 
Yorkshire, as described by Elgee (1, pp. 65-76). 
D. —Summary of Succession-Phases. 
Phase 7. Characterised by the presence of algae (Cystococcus, 
Glceocystis, 7'rochiscia), Ascobolus atrofuscus, seedlings and sprouting 
stools of Ulex nanus. 
Phase 2. Algae and soredial groups; mosses (Ceratodon, 
Funaria) ; sprouting stools of U. nanus, etc.; seedlings of shrubby 
members; also a number of herbaceous plants, especially Aim, 
Carex pilulifera, Poly gala, Galium, Rumex acetosella and Cuscuta ; 
many of the U. nanus seedlings dying away. 
Phase 3. Lichen-phase with thalli of Cladonia spp.; algae as 
in Phase 1, together with Mesotcenium ; increased phanerogamic 
vegetation. 
Phase 4. (a) Vigorous Calluna, Ulex nanus, Erica, with 
numerous lichens; algae as in Phase 3; disappearance of most of 
the herbaceous species (CUE phase). ( b ) (Poor Calluna) Similar to 
a, but with poorly developed shrubs and still more numerous 
lichens—this type is more particularly associated with the steeper 
slopes. 
Phase 5. (a) Considerable development of peat, Calluna 
dominant and Ulex nanus sub-dominant; frequent Hypnutn and 
Leucobryum, Cladonia sylvatica, Parmelia physodes, Mesotcenium and 
Glceocystis. {b) Similar to a, but with co-dominant Vaccinium and 
with less pronounced Ulex nanus ; very considerable accumulation 
of peat. 
Phase 6. Colonisation by Pinus, Betula, Pyrus, etc. 
East London College, December 18th, 1914. 
