IxxA'iii SPECIMEN, &c. 



8. Bushes and hedge plants. The shrubs which compose 

 this division differ from the plants of the forest in their smaller 

 size, and in the thinness of their leaves ; the herbaceous kinds 

 that grow among them are ordinarily climbing plants. 



9. Parasitical jplants ; that is to say, such as either absorb 

 the cambium already elaborated from the libei^ of the plant on 

 which they feed ; or merely derive the ascending sap from the 

 latter, converting it into nutriment themselves. The former 

 are destitute of leaves ; the latter provided with these organs — 

 the former require only to plant their suckers into the bark of 

 the vegetable which supports them ; the latter must insert them 

 into the alburnum or new wood. Such at least are M. De- 

 candolle's distinctions, with which Professor Lindley appears 

 to coincide. Both, however, separate from the class of true 

 parasites, those, which, like the common ivy [Hedera Helix,) 

 grow upon either dead or living vegetables, without deriving 

 any nourishment from them : Decandolle denominating these 

 latter, false parasites, Lindley, epiphytes, and such as these 

 may be conveniently thrown into the class either of forest or 

 bush plants, according to the kind of station which they aifect. 



These then are the botanical stations which I propose to 

 distinguish in my intended Index ; with regard to the habitats 

 of the plants that occur within the limits of this Flora, I 

 conceive, they may be placed with sufficient accuracy in one 

 of the last five columns, distinguished according to the geolo- 

 gical character of the substratum. The country compre- 

 hended within these limits includes indeed the whole range of 

 strata from the lyas to the tertiary clays, besides various dilu- 

 vial and alluvial formations ; but it does not seem likely, that 

 any decided difference in the character of the vegetation 

 should occur between one kind of clay or sand, and another, 

 merely on account of the distinction in their relative ages, 

 unless some corresponding variation can be detected in their 

 chemical or mechanical condition. I have, therefore, thought 

 it sufficient to divide the soils of Oxfordshire into five classes; 

 Istly. the gravelly, which, as it consists chiefly of the debris of 

 limestone rocks, may be regarded perhaps only as a modifica- 

 tion of a calcareous soil. 2ndly. the oolitic, of which the 

 neighbourhood of Oxford, where the substratum is not covered 



