i6o Flowers and their Pedigrefs. 



are mostly plants of the open wind-swept plains or 

 marshy levels, where the facilities for vjind-fertilisa- 

 tion are greatest and most constantly present' 



And now, from this illustrative digression, let us 

 hark back again to the junction point of the rushes, 

 whence alike the sedges and the grasses appear to 

 diverge. In order to understand the nature of the 

 steps by which the cereals have been developed from 

 rush-like ancestors, it will be necessary to look shortly 

 at the actual composition of the flower in grasses, 

 which is the only part of their organism differing 

 appreciably from the ordinary lily type. The blossoms 

 of grasses, in their simplest form, consist of several 

 little green florets, arranged in small clusters, known 

 as spikelets, along a single common axis. Of this 

 arrangement, the head of wheat itself offers a familiar 

 and excellent example. If we pull to pieces one of the 

 spikelets composing such a head, we find it to consist 

 of four or fife distinct florets. Omitting special fea- 

 tures and unnecessary details, we may say that each 

 floret is made up of two chaffy scales {e, d), known as 

 pales, and representing the calyx, together with a pair 



' The sedges are not, in all probability, a real na'tural family, but 

 are a group of heterogeneous degraded lilies, containing almost all those 

 kinds in which the reduced florets are covered by a single conspicuous 

 glume-like bract. It will be seen from the sequel that these bracts are 

 not truly homologous to the glumes or outer palese of grasses. 



