372 Stout: Bud-variation in Pelargonium 



and that cellular interaction is a potent factor in influencing cell 

 differentiation and in determining the physical characteristics of 

 such organs as leaves. 



The bud-sports which arise from the various Pelargonium 

 chimeras are, we may say, rather simple cases of variation due to 

 a mechanical rearrangement of the kinds of cells already present. 

 Their appearance is a confirmation of the rule that like produces 

 like in its application to cell lineage rather than evidence of spon- 

 taneous somatic mutation or variation. In this case the real 

 variation occurs when the white cells appear as the progeny of 

 green cells. The frequency of this spontaneous variation in 

 Pelargonium (and in other cases as well) and the real nature and 

 the causes of the process are problems for future solution. 



New York Botanical Garden. 



Literature cited 

 Baur, E. (1909a). Das Wesen und die Erblichkeitsverhaltnisse der 

 "varitates albomarginatae hort." von Pelargonium zonale. Zeits. f. 

 ind. Abst. u. Vererbungslehre. 1: 330~35i- 



(19096). Propfbastarde, Periklinalchimaren und Hyperchi- 

 maren. Ber. Deuts. Bot. Ges. 27: 603-605. 



(191 1). Einfiihrung in die experimentelle Vererbungslehre. 

 Berlin. 

 Strasburger, E. (1909). Meine Stellungnahme zur Frage der Propf- 

 bastarde. Ber. Deuts. Bot. Ges. 27: 511-528. 

 Winkler, H. (1907). Uber Propfbastarde und pflanzliche Chimaeren. 

 Ber. Deuts. Bot. Ges. 25: 568-576. 



(1909). Weitere Mitteilungen uber Propfbastarde. Zeits. Bot. 



1: 3I5-345- 



(1910). Ueber das Wesen der Propfbastarde. Ber. Deuts. 



Bot. Ges. 28: 116-118. 



