16 F, ORPEN BOWER. 
cells being maintained up to the mass of suspensors and 
embryonic tubes, which cover the apex of the root cap. 
Germination. 
On being exposed to conditions favorable for germination 
the seed swells, and the embryo begins to increase in length. 
The root is the first to push its way out through the ruptured 
testa. The elongation which produces this result takes 
place chiefly in the tissues of the root itself, the hypo- 
cotyledonary stem increasing at first only slightly in length.! 
The point of perforation of the testa is near to the apex of 
the seed, but is variable according to the position of the seed 
during germination. It is on the side which happens to be 
undermost (figs. 4, 5). The root in its growth pushes aside 
the persistent remains of the nucleus, together with the 
suspensors, and the apical part of the largely developed root 
cap. These may be seen in the germinated seedling attached 
laterally to the exterior of the root? (figs. 3, 4). 
Thus far the hypo-cotyledonary portion of the stem has 
extended only slightly. The cotyledons, however, and the 
upper part of the hypo-cotyledonary stem, begin now to in- 
crease in length, and the thickest part of the embryo is pushed 
out of the cavity of the endosperm. The room thus made is, 
however, filled by the growth of a peculiar excrescence from 
that side of the hypo-cotyledonary stem, whichis madeconcave 
by the curvature of the root downwards.? The first stages of 
development of this organ I have unhappily been unable to 
follow from want of suitable materials. Long before the 
escape of the cotyledons from the seed it may be found 
lying side by side with them in the cavity of the endosperm 
(fig. 2 4). In form itis wedge-shaped, but with the edge of 
the wedge (7. e. the apex of the organ) rounded. It is com- 
pressed in a plane parallel to that of the cotyledons. 
On searching for this lateral structure in the mature 
embryo before germination, no external trace of it was 
found, the swollen collar being, as described, uniform round 
the axis. Even on cutting sections of the hypo-cotyledonary 
1 According to Strasburger (‘ Conif.,’ p. 319), the hypo-cotyledonary stem 
usually elongates rapidly during the first stages of germination of the 
Conifer. 
* Cf., “ Description of Germination in Ephedra,” Strasburger, ‘Conif.,’ 
. 321. ; 
! 3 It is natural for seeds shaped like those of Welwitschia to lie on their 
side during germination. The possible case of a seed sown so that the 
radicle of the embryo should point vertically downwards, I have never had 
the opportunity of observing. 
