54 Study of Right- and Left- Handedness 



The difference between the two kinds of seedling may appear at 

 first sight to be of an insignificant character, and not worthy of serious 

 attention. That this is not so is amply evinced by the detailed account 

 of the morphology of the plant given by Schoute^ in his fine work on 

 the tillerage of cereals. It is there shown that the direction of folding 

 of the first foliage leaf has a direct connection with the side towards 

 which (in Barley, but not in other cereals) the axillary bud is displaced 

 from the median line, and also with the side of the plant on which the 

 first foliage leaf (after the prophyll) of every lateral axillary branch is 

 produced. The successive leaves, arranged distich ously on the stem, 

 normally alternate in their mode of folding^: thus all the leaf edges on 

 one side of the plant lie beneath those on the other. Since the first 

 foliage leaf of the axillary bud is always produced in the plane at right 

 angles to that of its subtending leaf and on the side towards its under- 

 lying edge, it follows that all the first foliage leaves of lateral axes of 

 the first order are towards the same side of the main axis. In these 

 and other ways it is demonstrated by Schoute that the mode of folding 

 of the first leaf is closely bound up with the symmetry and morphology 

 of the whole plant. 



Unfortunately reverse conventions are used by Schoute and myself 

 in distinguishing right- and left-handed plants. In what follows, 

 however, I propose to adhere to the convention adopted in my earlier 

 paper. 



Two-Rowed Barley. 

 In my previous paper it was concluded that there is no hereditary 

 nexus between successive generations of two-rowed Barley in respect 

 of right- and left-handedness. The statistics advanced were somewhat 

 restricted, and did not attain the same degree of accuracy as those 

 advanced in reply to the other questions proposed. Further results 

 have since been acquired and are given below in order to place my 

 previous conclusion on a firmer basis : for the conclusion itself is 

 unaltered. 



^ J. C. Schoute, "Die Bestockung des Getreides," Verh. d. K. Akad. v. Wetensch. 

 t. Amsterdam (Tweede Sectie) ; Deal xv. No. 2, pp. 8—24, Feb. 1910. 



2 Failure of this regular alternation of LH and RH leaves is mentioned by Schoute 

 {loc. cit. p. 20), and also by Stratton and Compton, "On Accident in Heredity, with 

 Special Eeference to Right- and Left-Handedness," Proc. Cambridge Phil. Soc. xv. p. 508, 

 1910. I made observations on twenty Maize plants, following them as far as 6 — 10 

 leaves, and noting the fold of each leaf as it appeared : of these thirteen showed the 

 normal alternation of RH and LH throughout ; the other seven showed a disturbance of 

 the regular sequence. 



