Stout: Bud-vartation in Pelargonium 369 



was the case in the plant from which the cutting was made. The 

 leaves were quite uniform in shape and in coloration and are quite 

 typical for the variety known as Madame Salleroi. Dr. L. H. 

 Bailey kindly made the varietal determination from leaves taken 

 from these branches and further states in a letter to the writer that 

 this variety has not been thus far placed specifically. As shown 

 in plate 20, the enclosed green cells fail to develop uniformly 

 toward the margin of the leaves, thereby leaving an irregular 

 marginal zone of pure white cells. In the central portion of these 

 leaves the enclosed green tissues show through the white. 



On the third branch, which is a lateral one, the leaves are quite 

 different. They are larger and the surface is green to the extreme 

 margin. These leaves are not, however, of a uniform green, for 

 through the central portion of each there is an irregular palmate- 

 shaped area of lighter green which is due to white cell-layers 

 enclosed between the upper and the lower green layers. In other 

 words the place relationship of the white and the green cells is 

 here reversed from what it is in the main part of the plant. In this 

 branch the plant has literally turned itself inside out. Micro- 

 scopical examination of free-hand sections confirmed the super- 

 ficial observations as to the color relations. 



In the black and white plate accompanying this article the 

 general pattern in the leaves is well shown by the different shades. 

 Since this plant has been under observation, about twenty leaves 

 have matured on this branch. As shown in plate 20 the amount 

 and distribution of the white tissue varies in the different leaves. 

 In some leaves there are small flecks of white scattered through 

 the green. A few of the leaves when about half developed show 

 traces of a dark zonal band which is a feature of various showy- 

 leaved Pelargoniums. When these leaves are mature, however, 

 this zonal band is faint. 



Baur notes a case of bud-variation identical with this one. 

 He states (1909 a, p. 333), that the plant which he designated as 

 Pel. 9 had white-bordered leaves but produced in 1908 a branch 

 having wholly green leaves but which were plainly of a yellowish 

 green in the center. The anatomical studies of these leaves (1909 

 a > P- 345) showed that the white cells were enclosed by the green 

 cells. 



