96 



Inheritance in Barley 



in which the rachilla bore two "paleae." These paleae contained no 

 traces of reproductive organs. 



Fig. 3. 



In 



There are a few hairs on almost all parts of the barley plant 

 the following regions hairs are abundant in varieties in general : 

 (i) Rachilla. 



(ii) Glumes. 



(iii) Awns (short, strong, spikes). 



(iv) The thin edges of the rachilla segments. 



(v) The lodicules (in the form of a fimbriation). 



(vi) Roots (root hairs and therefore not strictly analogous to glume, 

 etc. hairs). 



A comparison between Archer and Chevallier barleys for example 

 shows that the difference in the hairs of the rachillae exists, though it 

 is not so marked, in (ii), (iii), (iv), and (v). In the root hairs (vi), no 

 constant difference appears to exist. Thus it is suggested that one factor 

 governs the type of hair in all the regions (i) — (v). Examination of a 

 considerable number of barleys supported this view, but (iii) had finally 

 to be removed from the list on account of the evidence of the "dis- 

 tichum " barley H. d. persicum. This sub-variety has smooth awns but 

 both rachillae and glumes bear long bristly hairs. It is of interest to 

 note that another well-known smooth-awned barley, H. d. glahrum, has 

 smooth glumes, extremely short lodicule processes, and rachilla hairs 

 which are far shorter and finer than those of Chevallier. 



It is desirable to study this " parallel " development of the hairs of 

 different regions and, in particular, to investigate the root hairs, for upon 



