BOTANY contrast : long stretches of bare down dotted over with junipers or sweet- briar bushes, with here and there copses consisting to a considerable extent of white beam-tree (Pyrus Aria) , guelder-rose (Viburnum Lantana), dogwood (Cornus sanguinea), the abundance of various orchids and of some grasses such as the oat-grasses (Ave na pubesc ens and A. pratensis), as well as Bromus erectus, or the more sombre woods of yew (Taxus) and locally of box (Buxus), all tend to give a character to this formation very distinct from anything to be seen elsewhere in the county. Brewer (Flora of Surrey, 1863) gives sixty species as peculiar to the chalk and gault (including the Upper Greensand), some of which are now known elsewhere. Among interesting plants not mentioned above are the two milkworts (Polygala calcarea and P. amara), the horseshoe vetch (Hippo- crepis comosa), everlasting pea (Lathyrus sy/vesfris), Lathyrus birsutus, squinancywort (Asperula cynanchica) and bastard toadflax (Thesium humi- fusuni) ; among still-surviving orchids, Cephalanthera enstfo/ia, Orchis ustulata, the man orchis (Aceras anthropophora) , gnat orchis (Habenaria conopsea), musk orchis (Herminium mon-orchis), the bee and fly orchids (Ophrys apifera and O. muscifera), and the Turk's-cap lily (Lilium Mar- tagori). The flora of the Bagshot Sands formation shows much similarity to that of the Lower Greensand in its general and more striking features, except in those parts where the bog myrtle (Myrica Gale] or Agrostis setacea, two species which are peculiar to this formation, are plentiful. The hills however are not nearly so high and the pine woods are less extensive. Besides the above two species, the following are confined to the Bagshot Sands : the great burnet (Sanguisorba qfficinatis), a bur-reed (Sparganium affine], the bog-rush (Scbcenus nign'cans), slender cotton-grass (Eriophorum gracile], Scirpus pauctflorus, and a sedge (Car ex dioica). I find it difficult to characterize the London Clay by any special features : in many it resembles the Wealden, and like that formation is very poor in peculiar species. Fourteen are enumerated by Brewer, but nearly all of these have either been found on other strata or are introductions like the winter aconite (Eranthis byemalis) or blue anemone (Anemone apennina). A species of hare's-ear (Bupleurum tenuissimum) is however peculiar to the London Clay ; it is somewhat spasmodic in its appearance, but it has been gathered in one or two places in recent years. With regard to the Valley gravels which overlie the London Clay in many places ; the Reading and Woolwich beds ; and the Thanet Sands, I have no special observations, but according to Brewer the first-named possesses nineteen peculiar species, most of which may now be passed over for the reasons mentioned above ; there remain however a groundsel (Senecio viscosus), goosefoot (Chenopodium glaucum), fritillary (Fritillaria meleagris) and squill (Scilla autumnalis). For the Thanet Sands none are enumerated, while for the Reading and Woolwich beds two are named ; of these there may be mentioned Silene quinquevulnera now extinct, and there must be added the sulphur clover (Trifolium ocbroleucum) . In the lists of rare or characteristic species appended to the accounts of the separate districts but small notice has been taken of the very 37
