“…The most valuable kind of differentiating charactcr for cell-lineage studies is a nuclear one, since it will appear in each cell regardless of its morpho-Iogicnl position and can be seen in the meristematic tissues (Jones, 1937). Winkler (1935) and Lange (1927) obtained periclinal chimeras among the shoots formed at the union of grafted plants which 1 Heceived for publication September 15,19·tg. The author wishes to express his appreciation to Professor E. 'V.…”