296 Journal of Agricultural Research voi.x.no. 6 



the strong mechanical system of the lower flowering glume (Pi. 41, A). 

 In the case of the naked oat there is no such differentiation of the cells 

 of the lower flowering glume. As can be seen from Plate 41, B, the lower 

 flowering glume is quite thin and membranous; it is also unusually wide 

 and long. Its structure does not differ from that of the sterile outer 

 glumes. This weak structure of the lower flowering glume of the naked 

 oat, its unusually large dimensions in conjunction with the fact that it 

 does not adhere to the caryopsis at all, gives to it the appearance of a 

 sterile glume similar to the outer, empty glumes. 



The color of the glumes is pale yellow. The caryopsis is slender and of 

 light-yellow color (PI. 42, C). The nakedness of the kernels, the multi- 

 florous habit of the spikelets, the white color and absence of awns, are 

 the main characters of the naked oat involved in the cross dealt with in 

 this paper. 



THE HULLED PARENT, AVENA SATIVA PATULA 



The common hulled parent oat crossed with the naked oat is a pure 

 line, known in our record books as line 262, and was selected from a 

 variety known as the Victor. This variety is a black oat bred by a 

 commercial seed company. According to its catalogue, this oat "was 

 produced from six different parents, two of which were fall oats." Not- 

 withstanding its hybrid origin, this variety in general and line 262 in 

 particular breeds perfectly true in all characters. Line 262 was isolated 

 in 1 910 and has been grown every year since. A description of the 

 Victor variety has been given by Surface and Barber (7). Line 262 was 

 one used in the selection work carried on by Surface and Pearl (8). 



The Victor oat is characterized by a tall straw. Its height in the 

 garden averages about 155 cm. As seen in Plate 39, A, the head pos- 

 sesses a very long axis, long thin, drooping branches, covered with a 

 moderate number of spikelets. Toward maturity the slender wavy 

 branches yield to the weight of the grain, thus intensifying the drooping 

 appearance of the head. 



The grain of the Victor oat, as seen in Plate 46, A, is of medium size, 

 the caryopsis being firmly inclosed by the flowering glumes. The color 

 of the grain varies from dark brown to black. The lower grain bears a 

 medium strong, kneed, and twisted dark-brown awn. The base of the 

 grain is marked by a rather wide cleavage plane, similar almost to the 

 base of the intermediate type resulting from a cross between a wild 

 (Avena fatua) and a cultivated oat. On the majority of spikelets a few 

 rather long hairs may be found at the sides of the base of the lower grain 

 (PI. 46, A). The main characters of the Victor oat contrasting with 

 those of the naked oat are the hulled kernel, black color of grain, biflorous 

 habit, the rather heavy awns, and the pubescence at the side of the base 

 of the grain. 



