Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 62. (Budapest 1970)

Kováts, D.: Quantitative xylotomic investigations on the xylem of our home ash trees

width against the inverted ratio between medullary ray percentage and growth ring width. Changes in growth ring width is variable (heterogenous); there occur in the xylem also types with a growth in a pith—bark direction. I am deeply obliged to Professor S. SÁRKÁNY for his support of my work in the Institute of Applied Botany and Histogenesis, and also to J. STIEBER, assistant professor, for his valuable suggestions and availability of research material collected by him. I am most thankful to Miss S. BUNKE for her drawing of the Figures. Fig. 10. Correlation between growth ring width and fibre length. Fraxinus excelsior L. (Czech karst). — Accessory graph for the co- and counterdecurrence of the tension and pression wood graphs. — r.c. = rate of co-decurrence, — h.c. = heterogeneity of counterdecurrence