268 TRANSACTIONS OF THE [Srss. lxxviii. 



Phragmitis communis, Trin. ; Phalaris arundinacea, 

 Linn. ; Juncus effusus, Linn. ; and Iris Pseudacorus, Linn. 



On the bank the predominant trees are sycamore, beech, 

 oak, and ash. 



All along the cliff, owing to its height and deep clefts, 

 and the number of shade-bearing trees such as sycamore 

 and beech, the shade is very deep. Here, then, we find 

 again the typical sylvestral species such as Allium ursi- 

 num, Linn. ; Scilla nutans, Sm. ; Mercurialis perennis, 

 Linn. ; Primula vulgaris, Huds. ; Circaea lutetiana, Linn. ; 

 Teucrium Scorodonia, Linn. ; Lychnis dioica, Linn. ; Ger- 

 anium Robertianum, Linn. ; Brachypodium sylvaticum, 

 R. et. S. ; Arctium Lappa, Linn. ; Luzula sylvatica, Gaud. ; 

 Epilobium montanum, Linn.; Athyrium Filix-foemina, 

 Bernh. Less common but not unfrequent are Asperxda 

 odorata, Linn. ; Lysimachia nemorum, Linn. ; Hypericum 

 pulchrum, Linn. ; and H. Androsaemum, Linn. 



Owing to the inaccessibility of the cliff, numbers of these 

 shade-loving plants grow in wild luxuriance, forming with 

 the undershrubs tangled masses of vegetation which still 

 further add to the impregnability of their chosen strong- 

 hold. Among the undershrubs are Corylus Avellana, 

 Linn. ; Crataegus Oxyacantha, Linn. ; Rubus fruticosus, 

 Linn. ; Rosa canina, Linn. ; Primus spinosa, Linn. ; Sam- 

 bucus nigra, Linn. ; Pyrus Aucuparia, Gaertn. ; Lonicera 

 Periclymenum, Linn.; Hedera Helix, Linn. ; and Pteridium 

 aquilinum, Kuhn. These all assist in rendering the shade 

 of the ground plants denser, and their shelter more complete. 



On the rocks, where moisture is plentiful, mosses and 

 liverworts abound, while in drier situations Polypodium 

 vulgar e, Linn., Asplenium adiantum nigrum, Linn., and 

 Scolopendrium vtdgare, Sm., occupy otherwise bare portions 

 of the rock. At the top of the bank at the north end, 

 where a group of old beeches spread their dense shade, 

 Milium homum, Linn., alone of the ground plants finds 

 a congenial home, while other species which grow so 

 abundantly in the rest of the wood are absent or stunted. 



Considering the woodland plants from the point of view 

 of their adaptations, rather than from that of the associa- 

 tions which they form, one finds that three characteristic 

 types are well represented : — 



