890 Wilson—Plant Distribution in the 
The dwarf shade flora is represented by the following plants:— 
Viola Riviniana , Reich. Ajug a reptans ) L. 
Rubtis fruticosus , L. P ter is aquilina , L. 
Solid ago Virgaurea , L. 
All these species are found in small quantity. Solidago Virgaurea is 
the most abundant of the flowering plants, but this exists only in the 
vegetative condition. Viola Riviniana and Ajuga rep tans occur sparingly 
and rarely flower. Pteris aquilina is found in considerable quantity, but 
only produces small stunted leaves without sporangia. 
Felling takes place at intervals of about fourteen years, as in the copses 
on other soils in the neighbourhood. As before, the resulting flora can be 
divided into— 
(a) The plants of the shade flora which persist under the light 
conditions. 
(b) Species found only during the light period. 
(a) After felling has taken place there is a great increase in amount 
of Pteris aquilina . This plant rapidly becomes dominant and in the late 
summer and autumn covers the whole of the soil. Rubus fruticosus also 
develops greatly, and flowers in the second and following years. Solidago 
Virgaurea becomes abundant, flowering to a small extent during the first 
season and freely in the later years. Viola Riviniana increases in amount, 
and flowers abundantly. Anemone nemorosa , Endymion nutans , and Primula 
acaulis show little or no alteration. 
(b) The great majority of the plants which appear after felling arc 
biennials or perennials, and these do not flower during the first season. 
Few annuals have been observed ; of these, Mclampyrum pr a tense , L., is 
generally distributed ; Myosotis collina , Hoffm., is occasionally found. The 
following biennial and perennial plants occur in abundance :— 
Hypericum pulchrum , L. Juncoides pilosum, O. Kuntze. 
Calluna Erica , DC. Juncoides sylvaticum , O. Kuntze. 
Teucrium Scorodonia , L. Air a Jlexuosa , L. 
The occurrence of Calluna Erica and Air a Jlexuosa on a heavy clay 
soil is unusual, and on this account a careful examination was made to 
determine whether the clay in this locality was overlaid by a sandy deposit. 
No such layer, however, was found. The upper layers of the clay become 
very hard and dry during the summer, and this fact perhaps accounts for 
the prevalence on the London Clay of species in which xerophytic characters 
are considerably developed. Hypericum pidchrum and Air a Jlexuosa flower 
at approximately the same date, and in the early summer form a conspicuous 
feature of the vegetation. 
