36 
BULLETIN OF THE LABORATORIES 
Fig. 13. Ambrosia artemisiaefolia., Z., the first bud has here developed into a 
leaf-branch ; the second, into an inflorescence. 
Fig, I4. Ptelea trifoliata., Z., A, a case of “ Uebergiphelung”. B, enlarged 
section of a node of the same twig. 
Fig. 15. Ptero-carya Caucasica. 
Fig. 16. Coreopsis tinctoria., Nutt., the first bud developed into a flowering 
branch ; the second, into a flower bud. 
Fig. 17. Menispermum Canadense, Z., three buds bursting through the peti- 
ole scar. 
I, II, III, &c., the first, second, third, &c. oldest buds or their equiva- 
lents; ps, the petiole scar; If, the petioles of leaves; S, stems of leaf-branches; 
F, stems of flowering branches or peduncles of inflorescences. Figures are cited 
in the text by their numbers. 
