232 Inheritance of Tifjht and Loose Paleae in Oats 



a more detailed analysis of the entire plants in this generation of the 

 Nubischer cross proved that, although there are cases in which the 

 exact nature can only be ascertained when the basal tillers are also 

 taken into consideration, the main panicle is generally indicative of 

 the whole plant. The necessity for inspecting the other panicles arises 

 chiefly when the excess of either tight or loose grains is very great. 

 In such cases all, or most, of the paleae of the preponderating type 

 may be concentrated into the largest panicle, and the opposite extremes 

 have to be searched for on the subsidiary panicles. 



In the detailed analysis just referred to the panicles on each F^ 

 plant were taken separately, in the manner shown in Table II, and the 

 paleae borne on the different branches classified node by node, com- 

 mencing at the base. A " pure tight " palea has no paperiness, a "pure 

 loose" is entirely membranous, while an "intermediate" is a very 

 variable mixture of these two extremes (cf. Fig. 2). 



ABC 



Fig. 2. Types of paleae found on Fi plants. A == pure tight ; a grain 

 is shown in both dorsal and ventral view, the latter showing the 

 margins of the outer pale clasping the inner one. B = intermediate 

 forms. C = a pure loose palea. The sclerotised parts are repre- 

 sented black. 



The percentage of " pure tights," it will be observed, ranges from 

 20-4 7„ to 68-7 7,^; that of the "pure looses" from 7-8 7, to 46-8 7,. 

 The rise of the one appears to be correlated by the fall of the other, 

 not only when different plants are compared, but also in different 

 zones in the same plant. In plant A, for example, the first nodes 

 of the four panicles bear 77 pure tight and 7 jJure loose paleae out of a 

 total of 115, i.e. the relative proportions are as C7 °/o : 6'1 °/„. 



In the case of the second nodes they are as 45'8 /„ : 20'8°/„. 

 For the third nodes they are as ... 2(r8 /^ : 39 7o- 



For the fourth they are as 5 7°: 45 7„. 



And for the last they are as 7-4 7^: 44-4 7,. 



