the Embryo and Seedling in the. Gramineae. 213 
The second series is very incomplete, but serves to confirm the first, and in 
some cases to explain it, as the tissues are better differentiated. 
The bundles of the upper sheath behave as in Elettaria and Amomum. 
The lower sheath is comparatively short. The cotyledonary traces P and 
P' enter the stele of the hypocotyl as usual from either side. In this 
species the plumular traces seem to form three groups in place of two. In 
both the seedlings examined there were five traces at the top of the hypo¬ 
cotyledonary stele; in one of them the fivefold symmetry was retained 
throughout, in the other it became fourfold lower down. The protoxylem 
forms a single group in the centre. No well-marked root-plates are formed. 
The cauline roots arise from the base of the hypocotyl. 
Roscoea purpurea, Sm. The cotyledon in this species differs from that 
of Elettaria in the structure of its sheath. Of the three seedlings examined 
by us, we find two with no lower sheath, 
and the third with a very short one. The 
upper sheath is very well developed in all 
three seedlings, and its vascular skeleton 
corresponds exactly with that of the upper 
sheath in Elettaria . 
The vascular structure of the hypocotyl 
and first node differ in the two genera, but 
the points of difference are clearly corre¬ 
lated with the presence or absence of a lower 
sheath. Thus in that seedling of Roscoea 
which has a lower sheath, though a very 
short one, and is therefore nearest to the 
Elettaria type, there are about a hundred 
sections in which the upper sheath corre¬ 
sponds in structure to Diagram III in Text- 
fig. 30, except that in the lower ones the bundles are separated more 
widely. But whereas in Elettaria only the first leaf is enclosed by this 
region of the sheath, in Roscoea we find sections of the plumular axis. 
The length enclosed is about 1 mm. ; it begins at the base of the plumular 
bud, and ends in the first internode. The single sheath section which 
corresponds to IV, and the few below it which represent V, still enclose 
sections of the first internode. In Roscoea cauline roots are formed above 
the first node, and they penetrate the sheath in region V. 
Thus the cotyledonary traces P and P' run into a stele which is already 
giving off cauline roots, and has formed root-plates. In place of Diagram VI 
in Text-fig. 30 we have Text-fig. 32. There is no level in this seedling 
which corresponds to VII. In the intervals between the insertion of cauline 
roots, the stele of the hypocotyl resembles VIII in structure, though the 
Text-fig. 32. Roscoea purpurea , 
Sm. Diagram of first node in one 
seedling, corresponding to level VI 
in Text-fig. 30. 
