EFFECT OF MOISTURE 161 



down ; the pistillate ones of the same branch are above them, 

 in short, erect spikes. Each staminate flower consists of a 

 perianth and four stamens, the whole being situated, with two 

 other flowers of similar structure, in a scale. The pistillate 

 flowers are arranged, two together, on a scale ; each single flower 

 has two bracts, and consists of two carpels with two styles. An- 

 other shrub or tree characteristic of streams is the Willow. 

 There are a larger number of species belonging to the genus Salix. 

 It includes the Sallow (Salix Caprea\ found commonly in hedges, 

 to which it gives their golden appearance in March ; also several 

 willows, most of which require an expert to identify them accur- 

 ately. The willows have staminate catkins on one tree and pistil- 

 late on the other, and some species, e.g. the sallow, are pollinated 

 by insects. The staminate flower consists of two stamens and 

 a greenish nectary situated at the base of a bract. The pistillate 

 flower is composed of two carpels and also has a nectary. 



The herbaceous vegetation of 

 woods with numerous mountain 

 streams will naturally consist of 

 plants that like damp situations. 

 The most common plants in the 

 wetter parts will be the Golden Saxi- 

 frage, the Water Avens, Red Cam- 

 pion, Meadow-sweet, and Sedges. A B 

 In a mixed wood with a river running FI G. 47- A, staminate flower of 

 through it, and with dense shade, !! ow ' , B ' ^ istillate flower of 



Willow ; , bract ; , nectary. 



some of the most conspicuous plants 



found in August were : Sweet Cicely, Giant Campanula, Enchanter's 

 Night-shade, wild Strawberries and Raspberries, several grasses, 

 but chiefly the Reed Fescue (Festuca sylvatica), Wood Sage, 

 Figwort, Woodruff, etc. 



Many of these plants like deep shade and moisture ; two of 

 them, Sweet Cicely and Giant Campanula, are characteristic of 

 the north rather than of the south. 



The influence of trees on herbaceous vegetation is seen not 

 only in woods but in the lanes or pastures bordering on woods, 

 the trees of which overshadow the adjoining hedges. Plants 

 which belong to woods, such as Woodruff, Wood Sanicle, Wood 



VOL. IV. II 



