THE ACORN AND ITS GERMINATION tS 
a thin, brown, wrinkled, papery membrane, which is its 
own coat—the seed-coat, or testa (fig. 2, t). The extent 
to which the testa remains adherent to the seed, or to the 
inner coat of the pericarp, and both together to the 
harder outer coat of the pericarp, need not be commented 
upon further than to say that differences in this respect 
Fig. 2.—Sections of acorns in three planes at right angles to one 
another. A, transverse; B, longitudinal in the plane of the coty- 
ledons (1); C, longitudinal across the plane of the cotyledons; ¢, 
cotyledons; ¢, testa; p, pericarp; s, scar, and 7, radicle; pi, 
plumule. The radicle, plumule, and cotyledons together consti- 
tute the embryo. The embryonic tissue is at 7 and pl. The dots 
in A, and the delicate veins in B and ¢ are the vascular bundles. 
are found according to the completeness and ripeness 
of the acorn. 
Enveloped in its testa and in the pericarp, then, 
we find the long acorn-shaped seed, which seems at 
first to be a mere horn-like mass without parts. This 
is not the case, however, as may easily be observed by 
cutting the mass across, or, better still, by first soaking 
it in water for some hours; it will then be found that 
