i.] FLOWERS FERTILISED BY WIND. 7 



Indeed, it may be laid down as a general rule that 

 those flowers which are not fertilised by insects, as for 

 instance those of the Beech and most other forest 

 trees, are smallin size, and do not possess either 

 colour, scent, or honey. 



Before proceeding further let me briefly mention 

 the terms used in describing the different parts of a 

 flower. 



If we examine a common flower, such for instance 

 as a Geranium, we shall find that it consists, firstly, 

 of an outer envelope or calyx:, sometimes tubular, 

 sometimes consisting of separate leaves called sepals ; 

 secondly, an inner envelope or corolla, which is gener- 

 ally more or less coloured, and which, like the calyx, 

 is sometimes tubular, sometimes composed of separate 

 leaves called petals ; thirdly, of one or more stamens, 

 consisting of a stalk or filament, and a head or anther, 

 in which the pollen is produced ; and fourthly, a pistil, 

 which is situated in the centre of the flower, and 

 consists generally of three principal parts ; one or 

 more compartments at the base, each containing one 

 or more seeds ; the stalk or style ; and the stigma, 

 which in many familiar instances forms a small head 

 at the top of the style or ovary, and to which the 

 pollen must find its way in order to fertilise the 

 flower. 



But though the pistil is thus surrounded by one 

 or more rows of stamens, there are comparatively few 

 cases in which the pollen of the latter falls directly 

 on the former. On the contrary this transference is 

 in most cases effected in other ways generally by 

 means of the wind, of insects, or, in some cases, of 



