300 MONOCOTYLEDONS. 



(flowering glume) which is similar to the outer glumes but 

 sometimes bears a bristle (awn) at its tip, and an inner 

 scale (palea} which is thinner. Within the palea come the 

 three stamens and the pistil. The stamens when ripe have 

 long filaments, the filament being attached to the middle of 

 the anther; the pistil consists of a rounded ovary bearing 

 two stigmas. Note the two very small white scales, each 

 with a fringed upper margin ; these are called lodicules. 



Wheat, like other Grasses, shows several adaptations to 

 wind-pollination, though (like most other cultivated cereals) 

 it is largely self-pollinated. The spike is carried well up 

 into the air ; the pollen- grains are small and dry ; the ripe 

 anthers are pushed out of the flower by the elongation of the 

 filaments and dangle about freely owing to their " versatile " 

 (easily turned or swung) insertion on the end of the fila- 

 ment ; the hairy styles expose a large surface to catch pollen- 

 grains. 



Before flowering occurs plenty of food has been manu- 

 factured by the green leaves and stored up in all parts 

 of the plant leaves, stem, roots. The enormous extent of 

 the root-system of a single Wheat plant makes it easy to 

 understand what a large amount of food can be stored in 

 them, to be drawn upon for the maturing of the grains. The 

 roots penetrate deeply into the soil, and since each of the 

 " tillers " branches arising from the base of the shoot 

 produces scores of roots (especially from the lower " nodes ") 

 the aggregate length of the roots of a single Wheat plant 

 runs to hundreds of yards. 



When the Wheat is in full bloom the active life of the 

 plant as a manufacturer of food has reached its climax. It 

 has attained its full size, all its leaves are spread out in the 

 air, the roots have gained their greatest dimensions in the 

 soil, and the building up of new tissues has ceased. The 

 activity of the plant is now directed to utilising the surplus 

 food (stored in leaves, stem, and roots) in the production of 

 the seed. 



This will be more apparent if we consider the actual 

 increase in weight of the dry matter of the plant, excluding 

 the roots, at three stages in its life the end of March, 

 the end of June, and at harvest. Of the dry matter 

 of the ripe plant 20 per cent, was present by the end of 



