GERMINATION AND JUVENILE FORMS OF SOME OAKS 379 
Germination of Q. Rob ur var. pedunculata, according to obser- 
vations of H. Marshall Ward, 11 occurs in the spring. Sooner or 
later as the temperature rises in the spring, the embryo in the 
acorn absorbs water and oxygen and swells, and the little radicle 
elongates and drives its tip through the ruptured investments at 
the thin end of the acorn and at once turns downward and forces 
itself slowly into the soil. 
With us the acorn germinates abundantly in the fall soon after 
it falls to the ground, in September or October, vary- 
ing with the season. In the greenhouse it tested 90 per cent 
Fig'. 67. — Germinating Russian oak ( Quercus Robur var. pedunculata ) ; 
1, condition on October 4 ; 2, condition on October 20 ; 3, condition on 
October 30 ; 4, trichomes of stem ; 5, triehomes of leaf. Drawn by C. M. 
King. 
germination. The plumule pushed out near the upper end, the 
young stem was slightly pubescent, the trichomes of the stem 
generally occurring singly, long pointed, straight or slightly 
curved, cell wall -colorless, thick, contents brown, the lower 
leaves were scalelike, these successively larger, the fully formed 
penni-nerved leaves with margins of rounded teeth, upper sur- 
face of leaf shining, lower surface paler in color ; midrib promi- 
n H. Marshall Ward. The Oak, 19. 
