The Woodlands of England. 145 
is a good deal of oakwood on soil which is shown on the Drift 
maps of the Geological Survey as Chalk; but such woods are 
invariably found to be developed not on the chalk itself but on a 
non-calcareous soil overlying the chalk. On the other hand the 
plateau of the Chilterns, similarly covered with non-calcareous clays 
and loams, is often occupied by beech, or by beech and oak mixed, 
though sometimes, as in the cases above described, it bears typical 
oakwood. 
The beech is not only the dominant tree in the beech association; 
it typically forms an almost pure high forest of beech in close 
canopy. Occasionally an ash is met with, occasionally a white 
beam tree ( Pyrus Aria), hardly ever an oak. The yew ( Taxus 
baccata) is found in many beechwoods forming a distinct layer 
below the crowns of the dominant trees. There are practically 
no shrubs in a normal beechwood, the light penetrating the canopy 
being insufficient for their growth ; but on the outskirts of the 
wood there is frequently a rich and varied scrub of such species as 
Cratcegus monogyna, Pyrus Aria, Viburnum Lantana, Rhamnus 
catharticus, Cornus sanguiuea, Euonymus europaus, Prunus 
spinosa, Corylus Avellana, Acer canipestre, Sambucus nigra, 
Juniperus communis, and Taxus baccata, with the climber Clematis 
Vitalba. These species will be recognised as characteristic shrubs 
of the ashwood associations ; and with them may often be found 
much ash, which sometimes grows up to form a regular ashwood 
with its varied undergrowth. 
Under the close canopy of the beechwood itself, the shade is 
typically so deep as to exclude all ground vegetation except certain 
saprophytes; but in more open spots Mercurialis perennis becomes 
generally dominant, while Sanicula europcea, Viola Riviniana and 
V. Reichenbachiana, Fragaria vesca, and Circcea lutetiana are 
locally dominant. Viola hirta is abundant and charcteristic. The 
orchids Cephalanthera pollens and Helleborine violacea are also 
characteristic, while in the deeper humus the colourless saprophytes, 
Monotropa Hypopitys and Neottia Nidus-avis, are frequent, even in 
the deepest shade. Atropa Belladonna, Daphne Laureola, Ruscus 
aculeatus, and more rarely, Helleborus viridis are characteristic of 
more open spots on the outskirts of beech woods. 
The following is a summary of the types of woodland distin¬ 
guished in the present paper :— 
