Xxxii FLORA OF BERKSHIRE 



These detached areas of the Lower Greensand form a light sandy 

 soil, which to the botanist are so many oases, since many local and 

 rare plants are found on them, and the flora exhibits a striking 

 contrast to that of the preceding formation. Some of the species 

 which are found on the Lower Greensand may be enumerated 

 — Papaver hybridum, Sisymbrium thalianum, Teesdalia nudicaulis, Tunica 

 proli/era, Silene anglica, Cerastiiim semidecandrum^ Sagina ciliata, S. apetala, 

 SperguJa atvensis, S. sativa, Buda rubra, Hypericum humifusum, H. pulchrum, 

 Geranium lucidum, Erodium cicutarimn, Trifolium arvense, T. striatum, Orni- 

 thopus, Vicia lafhyroides, Rubus idaeus, var. anomaJus, R. stdcatus, R. Cole- 

 manni, R. mercicus, var. bracteatus, R. oigocladus, var. Neivbouldii, R. affinis, 

 R. suberectus, R. pyramidalis, Rosa tonientosa, var. pseudO'moUis, Gnaphalium 

 sylvaiicum, Anthemis arvensis, Tanacetum, Chrysanthemum segetum, Filago 

 minima, F. germanica, Solidagoj Erigeron acre, Seiratula, Centaurea Cyanus, 

 Hieracium boreale, H. sciaphilum, H. rigidum, var. scabrescens, H. umbellatum, 

 Jasione montana, Erica cinerea, CaUuna, Lycopsis arvensis, Mijo.^otis versicolor, 

 M. collina, Echium, Digitalis, Veronica officinalis, Melampyrum pratense, 

 Stachys arvensis, Polygonum dumetorum, Plantago Coronopus, Scleranthus 

 annuus, Betula, Carex Jeporina, C. piluUfera, Agrostis canina, Beschampsia 

 Jlexuosa, Aira caryophyllea, A. praecox, Koehleria, Festuca sciuroides, Nardus, 

 Blechnum, and others. 



The Gault consists of bluish clay, usually calcareous and often 

 micaceous, with some bands of phosphatic nodules. The strip of 

 country along which it comes to the surface is flat with a stiff, heavy 

 soil, and, as is the case with the Oxford and Kimeridge Clays, un- 

 interesting in its botanical features. Where Drift deposits occur 

 upon it, they give a little variety to its surface and flora. 



The Gault occupies a zone varying from one to three miles in width, 

 which extends across the county from the Wiltshire to the Oxfordshire 

 border. This zone is fairly even on its northern margin, but is very 

 irregular on its southern side. 



The usual plants which are to be found on argillaceous soils occur in 

 the Gault, but from the sparsity of woodland many sylvan species are 

 absent. Senecio erucifolius is common. Ex>ilobium tetragonum, and a hybrid 

 of that species with E.parvi/lorum, have been gathered near Uffington. 

 Euphorbia exigua, var. retusa, occurs in some of the arable fields. Mentha 

 piperita is found in one of the ponds. The marshy pastures afford 

 Memjanthes, Orchis incarnata, and Ophioglossum. The Brambles are very few 

 in number, and are chiefly Rubus ulmifolius, R. coryli/olius, R. dumetorum, 

 R. caesius, and i2. leucostachys. 



The Upper Greensand occupies a belt of country from the Wilt- 

 shire border on the west to the Oxfordshire border on the east. It is 

 five or six miles across on its eastern side, that is from Wittenham to 

 Aston Tirrel ; from this width the belt gradually narrows till it almost 

 thins out at Woolstone. 



