BOTANY 



THE RIVER DRAINAGE OF BERKSHIRE 



as used for dividing the county into botanical districts must be next considered. Berkshire is 

 wholly in the Thames basin, the area of which is about 5,162 square miles, or over 3,300,000 

 statute acres. For no miles of its course the Thames forms a boundary for Berkshire. At 

 the point of its touching Berkshire near Lechlade it receives a small stream, the Cole, which 

 rises from the chalk hills of north Wiltshire near Idstone. 



It is this small portion of our county, as well as the long strip, chiefly of Oxford clay, 

 and the corallian oolite ridge which stretches from Oxford to Faringdon, which is com- 

 prised in our first division, namely 



i. THE Isis OR UPPER THAMES, 



which corresponds to the district ' Thames 3 ' of Preston's Wiltshire Flora, and to the district 

 ' 5. Isis or Upper Thames ' in my Oxfordshire Flora. 



It would perhaps have been well to subdivide this into two parts, that drained by the 

 Cole, and the second into that portion drained by the main stream from Faringdon to 

 Oxford ; the Cole itself contains a country with very varied geological character, since the 

 stream drains the upper and lower chalk, the upper and lower greensand, the gault, the 

 Kimeridge clay, the corallian oolite and the Oxford clay, while the portion drained by 

 the main stream only consists of the two latter, and it is consequently much less diversified in 

 scenery and much less rich in vegetation than the former. The northern boundary of the 

 district is the Thames, the western boundary is the Cole and the county of Wilts, and the 

 southern boundary is practically that of the turnpike road between Oxford and Faringdon. 

 From this highway very extensive and pleasing prospects can be obtained, and many interesting 

 species occur even by the roadside. In this district the beautiful estate of Wytham is con- 

 tained, and this yields several varieties. It is the only locality known with us for the rose 

 Rosa agrestis, and it is the most northern locality for the orchid Cephalanthera pollens. In 

 the woods still grow the beautiful wood vetch (Ficia sylvatica), and the deadly nightshade 

 (Atropa Belladonna), the yellow star of Bethlehem (Gagea fascicularis), the henbane (Hyoscyamus 

 niger), the hound's tongue (Cynoglossum ojficinale), the gromwell (Lithospermum officinale), the 

 herb Paris (Paris quadrifolia), the elecampane (Inula Helenium), the spurge laurel (Daphne 

 Laureola), the wild everlasting pea (Lathyrus sylvestris), the large burnet saxifrage (Pimpinella 

 major), the small buttercup (Ranunculus parviflorus], Samolus Valerandi, the bog pimpernel 

 (Anagallis tenella), the spindle tree (Euonymus europaus) and birds' nest (Hypopitys) occur, as 

 well as a most profuse growth of Carex pendula. 



Between Wytham and Faringdon the district of the upper Thames is well cultivated, 

 heathland and true bogland being almost entirely absent, so that Drosera, Narthecium, Erica, 

 Calluna, Juncus squarrosus, Plantago Coronopus, Anthemis nobilis and Salix repens, so common in 

 the south of the county, are very rare or wanting, nor are the natural woods very extensive. 

 On the corallian oolite the great thistle (Cnicus eriophorus) is found, and also the zigzag 

 clover (Trifolium medium), the mullein (ferbascum nigrum), and the calaminth (Calamintha 

 montana), while the grasses Bromus erectus, Brachypodium pinnatum and Avena pubescens are 

 common, and Keeleria cristata local. The Thames meadows have a rich riparian vegetation, 

 which includes the great spearwort (Ranunculus Lingua), the bitter cress (Cardamine amara), 

 the bogbean (Menyanlhes trifoliata), the stitchwort (Stellaria palustris), the louse wort (Pedi- 

 cularis palustris), the sulphur wort (CEnanthe silaifolia), the bistort (Polygonum Bistorta), and the 

 elegant water parsnip (Sium latifolium). It has one feature of special interest in the occurrence 

 in some plenty over a limited area of the water germander (Teucrium Scordium), a very rare 

 and local and decreasing species in Britain, which was first made known as a British species 

 from the neighbourhood of Oxford in 1552, but which appears to be quite extinct on the 

 Oxfordshire side of the Thames. In some of the sluggish waters grow the bladderwort 

 (Utricularia vulgaris), the water primrose (Hottonia palustris), and the frog bit (Hydrocharis 

 Morsus-ranie. A characteristic grass is Bromus commutatus. In the main streams there are 

 quantities of pondweed, but they chiefly consist of common species, Potamogeton interrupts 

 being especially a noticeable feature, with the buttercup (Ranunculus fluitans). Here and there 

 the beautiful fringed water lily (Limnanthemum peltatum) occurs, and both the common yellow 

 and white lilies abound. 



The ornamental waters at Buscot have both species of reed mace (Typha), and the 

 mare's tail (Hippuris), and Lotus tenuis, and the leopard's bane (Doronicum Pardalianches) 

 occur in the vicinity. In Buckland Park the bear's foot (Helleborus viridis) and the box tree 



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