346 



GENETICS IN RELATION TO AGRICULTURE 



FIG. 143. Details of wheat inflorescence. 



The smaller spike is Fife and at its left is shown a Blue Stem spike. In the lower right- 

 hand corner is a spike from which small late flowers have been removed preparatory to 

 crossing. 



At 2, spikelet, natural size, with a few joints of the rachis;/and g are flowerless glumes; k, 

 florets bearing seeds; r, rudimentary florets. 



3, a single flower closed just after flowering, X3. 



4A, longitudinal diagram before flowering, X2.5; anthers marked a; ovary, o; stigma, 

 ; filament, /. 



4fi, diagram of floret just after flowering, X3, showing how anthers are held within the 

 envelope. 



5, transverse diagrammatic section, or floral plan, as is made by cutting across 4A at x, 

 X6;/0, flowering glume or lemma; p, palea; a, anthers; s, stigma. 



6, flowerless glume; 7, flowering glume or lemma; 8, palea; all slightly reduced. 



9, lodicule, X4, shown also at L in 4fi. 



10, cross-section of anther, X26; showing the pollen sacs and the central mass of tissue 

 to which they are attached. 



