1003 
Medullary Rays of Quercus. 
relationship, so that Q. ( Pasania) densiflora falls out of line with the other 
species: the parallelism does not hold good of Indian species, possibly 
because of climatic differences. 
It is a pleasure to thank Professor Jeffrey of Harvard University, and 
Mr. R. S. Pearson, Imperial Forest Economist in India, for their kindness 
in supplying the material used in this investigation from America and India 
respectively. 
Literature;. 
Abromeit, J. ('84) : Ueber die Anatomie des Eichenholzes. Berlin. 
Bailey, I. W. (TO) : (i) Notes on the Wood Structure of the Betulaceae and Fagaceae. Forestry 
Quarterly, vol. viii, No. 2. 
- (TO) : (2) Reversionary Characters of Traumatic Oak Woods. Botanical Gazette, 
vol. 50, p. 374. 
- (’ll) : The Relation of the Leaf-trace to the Formation of Compound Rays in Lower 
Dicotyledons. Annals of Botany, vol. xxv, p. 225. 
Eames, A. J. (TO) : On the Origin of the Broad Ray in Quercus . Botanical Gazette, vol. 49, 
p. 161. 
Groom, Percy (TO) : Remarks on the Oecology of Coniferae. Annals of Botany, vol. xxiv, pp. 257-8. 
Jost, L. (’01): Ueber einige Eigenthumlichkeiten des Cambiums der Baume. Botan. Zeitung, 
Bd. lix, p. 15. 
Sanio (’63) : Vergleichende Untersuchungen iiber die Zusammensetzung des Holzkorpers. Bot. 
Zeit., Bd. xxi. 
EXPLANATION OF FIGURES IN PLATES LXXIV-LXXVI. 
Illustrating Prof. Groom’s paper on the Evolution of the Annual Ring and Medullary 
Rays in Quercus. 
Figs. 1-12 are of transverse sections with a magnification of 12.5. Figs. 13-32 are of 
tangential sections of the broad medullary rays, with a magnification of 12, excepting where special 
magnifications of 25 are recorded. 
Figs. 
1. Q, hypoleuca. 
2. Q. Etnoryi. 
3. Q. chrysolepis. 
4. Q. densiflora. 
5. Q. virginiana. 
6 . Q. agrifolia. 
7. Q. tomentella. 
8 . Q. semecarpifolia. 
9. Q. glauca. 
10. Q. lamellosa. 
11. Q. incana. 
12. Q.fenestrata. 
13. Q. Macdonaldi. 
Figs. 
14. Q. acuminata. 
15. Q. bicolor. 
16. Q. sessiliflora. 
17- Q» georgiana. 
18. Q. Douglasii. 
19. Q. Emoryi. 
20. Q. arizonica. 
21. Q. hypoleuca. 
22. Q. Engelmanni. 
(a) x 12. 
(b) x 25. 
23. Q. chrysolepis. 
Figs. 
24. Q. agrifolia. 
(a) x 12. 
(*) * 25. 
25. Q. virginiana. 
26. Q. tomentella. x 25. 
2 7. Q. densiflora. 
28. Q. lamellosa. 
2 9. Q. glauca. 
30. Q. semecarpifolia. 
31. Q. incana. 
( a ) vertically divided ray. 
(b) obliquely divided ray. 
32. Q. fenestrata. 
