26 BRITISH FLOWERING PLANTS chap. 



aqueous leaves. Again, iii still air the conditions, 

 except so far as they are modified by the weight, would 

 approximate to those of water, but the more the plant is 

 exposed to wind the more would it require strengthening. 

 Hence perhaps the fact that herbs, which, of course, are 

 less exposed to wind, so much oftener have finely-cut 

 leaves than is the case with trees. We may instance 

 those of many Geraniums, Umbellifers, Delphiniums, 

 Buttercups. 



There are, moreover, many groups of plants which, 

 while habitually herbaceous, contain some shrubby 

 species, or vice versa. Let us take some groups of this 

 description in which the herbaceous species have their 

 leaves much cut up, and see what is the character of 

 the foliage in the shrubby species. The vast majority 

 of Umbellifers are herbaceous, and with leaves much 

 divided, the common carrot being a typical example. 

 One European species, however, Bu2:)leuruifnfruticosum, 

 is a shrub attaining a height of more than 6 feet, and 

 has the leaves coriaceous and entire. 



Common G-roundsel {Senecio vulgaris) again is a 

 low herb with much cut leaves. Some species of 

 Senecio, however, are shrubby, and their leaves assume 

 a totally different character, Senecio laurifolius and 

 S. populifolius having, as their specific names denote, 

 leaves respectively resembling the Laurel and Poplar. 

 In the genus Oxalis, again, there is a slirubby species, 

 O. Laureola, with leaves like those of a Laurel. 



One common type of leaf is that of which the Laurel 

 may be taken as an example. Such leaves are more 

 or less oval, somewhat tough, caducous or evergreen, 

 and with the stomata, as a rule, on the lower surface. 

 They are adapted to resist wind, and are charac- 

 teristic of trees and shrubs. To this type belong, 

 besides those of Laurel, the Laurustinus, the Way- 

 faring tree. Evergreen Oak, Holly, Beech, Hornbeam, 

 Elm, Pear, etc. 



In others the leaves are larger, but, perhaps as a 

 protection from the wind, are pinnate, with more or 



