Wilson—Plant Distribution in the 
898 
of the vegetation of the two soils 
found on the London Clay, but s 
Potentilla silvestris , Neck. 
Soli dago Virgaurea , L. 
Calhina Erica , DC. 
Stachys Be Ionic a, Benth. 
The following are abundant on 
ally found on the Clay with Flints: 
Hypericum pulchrum, L. 
Teucrium Scorodonia, L. 
of interest. The following species are 
absent from the Clay with Flints :— 
Juncoides sylvaticum, O. Kuntze. 
Air a flexuosa , L. 
Air a caespitosa , L. 
Festuca ovina , L. 
the London Clay, but are only occasion- 
J unco ides pilosum , O. Kuntze. 
Pier is aquilina , L. 
Mercurialisper enniS) L., and Adoxa Moschatellina , L., while abundant 
on the Clay with Flints, are absent on the London Clay, and the following, 
while found abundantly on the former deposit, are only occasionally present 
on the latter :— 
Anemone nemorosa , L. 
Panicula europaea , L. 
Dipsacus sylvestris , Huds. 
Myosotis sylvatica, Hoffm. 
Echium vulgare , L. 
Euphorbia amygdaloides , L. 
Endymion nutans , Dum. 
At present no definite reasons for the great difference in the vegetation 
of the two deposits can be given. It is, however, interesting to note that the 
flora of the London Clay is distinctly xerophytic in character, while that of 
the Clay with Flints shows few or no adaptations against drought. This 
matter will be further discussed in the second part of this paper. 
The following species are, in this neighbourhood, found exclusively on 
the Chalk:— 
Viola hirta, L. 
Helianthemum Chamaecistus , Milk 
Reseda lute a , L. 
Poterium Sanguisorba , L. 
Origanum vulgare , L. 
Clinopodium Calamintha , O. Kuntze. 
Clinopodium Acinos, O. Kuntze. 
Clinopodium vulgare , L. 
Thymus Serpyllum , L. 
Ophrys muscifera , Huds. 
Taxus baccata, L. 
Anomodon viticulosus , H.T. 
The following are almost confined to the Chalk, but are occasionally . 
found on other formations :— 
Hypericum hirsutum , L. Cornus sanguined , L. 
Linum catharticum , L. Viburnum Lantana , L. 
Euonymus europaeus , L. 
In several cases plants found abundantly on the Chalk are replaced on 
the non-calcareous soils by closely-related species. Such parallel species 
have been described by Kerner (9) in the Alps, Viola hirta is abundant on 
