INFLORESCENCE AND FLOWERS—FRUIT AND SEED 1381 
all the available nourishment to itself. Consequently 
the advancing ovary is soon filled by one avule—the 
other five and two of the chambers being pressed to one 
side by it. 
In a few weeks the ovary and its cupule have in- 
creased considerably in size, and the one successful 
ovule, with the rapidly developing embryo in the 
Fia@. 36.—Sections of acorns in three planes at right angles 
to one another. A, transverse; B, longitudinal in the 
plane of the cotyledons (2); ©, longitudinal across the 
plane of the cotyledons; ¢, cotyledons; ¢, testa ; p, peri- 
carp; 8, scar, and 7, radicle; pl, plumule. The radicle, 
plumule, and cotyledons together constitute the embryo. 
The embryonic tissue is at ry and pl. The dots in A, and 
the delicate veins in B and C are the vascular bundles, 
embryo-sac in its interior, occupies nearly the whole of 
its cavity; the remains of the two aborted chambers 
and the five unsuccessful ovules being traceable as tiny, 
shrivelled remnants in one corner. The walls of the 
ovary then gradually change into the polished brown 
walls (pericarp) of the fruit; the walls of the ovule 
become the coat (testa) of the seed; and the embryo 
K 2 
