HARRIS AND AVERY: MORPHOLOGICAL VARIATIONS 111 



or the onerous preliminary examination of nearly a half a 

 mibn seedlings we are greatly indebted to Miss Edna K. Lock- 



wod, Miss Margaret Gavin and especially to Miss Lillie Gavin. 







PRESENTATION AND ANALYSIS OF DATA 



he slightest abnormality which w r e have been able to discover 

 occrring in considerable numbers of bean seedlings is the vertical 

 sep; ation of the two normally opposite cotyledons. So imper- 

 cepble is the line of transition between normal and abnormal that 

 per^nal equation must play some part in classification. The 



cotjedons may be much more widely separated. The variation 

 is amrely graduated one, with no sharp lines of demarcation be- 

 twei the different degrees of separation. Generally we have 

 recc;nized three grades, but because of the rarity of plants with 

 moi widely separated cotyledons we have in this paper grouped 

 ourlata into two classes only. The first comprises plants with 

 cotjedons 2-3 mm. apart. The second includes all those in which 

 themre more distant. 



he number as well as the position of the cotyledons may vary. 

 Plars with three instead of two cotyledons fall into two groups ; 

 the* with the normal pair of primordial leaves and those with a 

 whd of three leaves. The latter are by far the more abundant, 

 .bnormality developed subsequently to the selection of the 

 seecngs in the preliminary sorting may affect either the inter- 

 nod between the second and the third nodes, that is, between the 



orirordial leaf whorl and the point of insertion of the first com- 



; ooud leaf or leaf whorl, or it may be confined to the number or 

 ;truture (or number and structure) of the leaves inserted at the 

 :hir node. 



i the original selection of individuals abnormal in the char- 

 icte? of the first or second node, only those with sensibly normal 



, : ixe&amp;lt;(hypocotyl and epicotyl) were chosen for the purposes of the 

 )reait study. 



. Vo types of abnormality in the axis beyond the second (the 

 )rirordial) node have been considered. 



iie first is a sensible broadening of the axis, identical with or 



, imiir to fasciation. This is a graduated character. The line of 

 lemrcation between normal and abnormal is not clearly marked. 



