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28 MISS M. G. SYKES ON THE SEEDLING AND 
Section I.—DzEvELOPMENT OF OUTWARD FORM. 
The earliest stages in the formation of the seedling from the embryo have been 
described by Bower*; and in his later paper he gives a very clear account of the 
method of growth in older seedlings. 1 have, however, been fortunate enough to obtain 
plants of apparently intermediate age which have furnished some further points of 
considerable interest. i 
Stage 1.—Pl. 34. fig. 1 shows a seedling about thirteen months old. Its cotyledons 
are still attached and the feeder inserted in the husk of the seed. The hypocotyl is as 
yet fairly uniform in thickness, save for a slight swelling at S. The bases of the 
cotyledons are continuous, and at each of the two points where the margins of the bases 
join oeeurs a small swelling (R) T, which, since it appears to have passed unnoticed by 
earlier observers, is possibly unusually prominent in this seedling. The two plumular 
leaves are already well developed, and, alternating with the cotyledons, are attached 
within the ridge formed by the fused cotyledonary bases. The stem apex is as yet only 
slightly depressed, and is so little differentiated as to be hardly distinguishable: on 
either side of the apex occurs a small conical process, which, on account of its position, 
is to be regarded as a bud borne in the axil of the cotyledon 1. 
At this stage the cotyledons are green and living, but their bases are mainly composed 
of corky cells similar to those found on the exterior of the stem. In seedlings 
representing stages intermediate between those shown in figs. 1 and 2 examined 
from time to time while growing at the Botanic Garden, it was scen that the steadily 
broadening plumular leaves pressed against the bases of the cotyledons, and, some 
time before the latter began to wither, caused a split to appear in the region of 
pressure, whereby the base of the cotyledon became bifurcated. 
The cotyledons then gradually dry up and wither away. They have already withered 
in the seedling shown in Pl. 34, figs. 2a, 26; their ragged bases are seen at C (fig. 20). 
There is no definite absciss layer formed, but the cotyledons wither and gradually drop 
off, owing to the slow decay of the tissue at their base; the continuity of the two 
primary vascular bundles is preserved for a considerable period. 
Stage 2.—At this stage the upper portion of the hypocotyl is much swollen and 
fusiform (Y, fig. 2). In this partieular seedling the feeder could no longer be 
distinguished, but it was still present in the larger seedling drawn in fig. 3; here it is 
clear that only the upper part of the hypocotyl has swollen. The unswollen portion of 
the hypocotyl (U, figs. 3 & 4) is usually of considerable length, as in this seedling 
(fig. 3), but it is occasionally quite short; one case was examined in which its length 
was somewhat less than that of the swollen portion; and in another example, at about 
the stage shown in fig. 3, the feeder was placed immediately beneath the swollen 
* Bower, I. pp. 15-20. 
T It will be seen that there is a special vascular supply to these swellings, a fact which adds to the interes s 
already awakened by their outward appearance (Pl. 35. figs. 15a & b). 
t Bower, I. and Il. ; cf. also Henriques, J. A., Bot, Centralbl. (1909) no. 47, p. 68. 
