A case of bud-variation in Pelargonium 
A. B. STOUT 
(WITH PLATE 20) 
The precise nature of bud-variation is not satisfactorily known. 
No adequate classification of the various kinds of bud-variation 
has been made. Recent investigations regarding the nature of 
plant chimeras indicate that some of the phenomena generally 
considered as bud-variation are associated with chimeras and are 
to be explained by the nature of the chimeras. Observations and 
experiments are now being made at the New York Botanical ~ 
Garden on various types of bud-variation. In the studies on 
Pelargonium one case has arisen which seems of special interest 
in its bearing on the nature of bud-sports from plants that are 
chimeras. 
Baur (1909 a and 6; 1911) has recently shown that the variega- 
tion in the case of the ‘‘albomarginatae” varieties of Pelargonium 
zonale is due to the presence of white and green cells which are 
sharply distinct and which occupy a characteristic position in 
relation to each other. It has been long known that the paler 
tissue of these variegated plants owes its characteristics to a lack 
of chlorophyl in its cells. Baur shows that the plastids are present 
in the white cells but are colorless. 
Baur further claims that this arrangement of green and white 
cells in the leaf can be explained by the arrangement of the corre- 
sponding tissues in the growing point and actually shows that in 
the plants whose leaves have layers of white cells on the exterior 
there is in the apex of the stem a cap of white cells over the greener 
cells beneath. In such plants the relative position of the white 
and the green cells is maintained throughout the development of 
the leaves. : 
By further study Baur (1909 a; 191 1) found that in other cases 
these two kinds of cells may be variously arranged with reference 
to each other. In some plants various stems and leaves show a 
367 
