226 
Lang . — Studies in the Morphology and 
In the examples most clearly comparable to Helminthostachys , a canal 
or slit extends downwards and inwards from the axil of the leaf. Usually 
the outer portion of the slit is completely occluded, and no trace of it is 
evident passing through the periderm. The inner portion of the slit is 
always recognizable, and though it does not extend so far towards the stele 
as in Helminthostachys , it exhibits a similar slight curvature forwards at the 
inner end. The cells bounding the side of the slit away from the apex of 
the stem have the same glandular appearance as was noted by Gwynne- 
Vaughan in Helminthostachys ; these cells, which often break down in 
preparations, extend round to the inner end of the canal. There is a more 
or less marked projection of the tissue of the inner wall of the slit, i. e. of 
the surface belonging to the stem, into the concavity of the canal. The 
cells forming this projection are small and have a healthy appearance. The 
general relations of the whole structure to the leaf-trace and the regions as 
described above are shown in the two longitudinal sections (Phots. 25, 26). 
Phot. 28 shows the position of the vestigial bud in relation to the leaf-gap 
and the subtending leaf-trace, the section passing through the base of the 
vestigial bud below the level of the canal. Phot. 27 is a similar section of 
a larger stem less highly magnified ; it passes through the slit leading down 
from the leaf-axil. 
While this description and these figures serve to show the appearance 
and structure of these vestigial buds, the position of the actual apex is still 
a matter of doubt, and the detailed consideration of this question must be 
postponed. I incline to regard the apex as being situated either at the 
inner end of the slit or towards the leaf-base, and not to be represented by 
the more marked projection of tissue from the stem side of the slit. Com- 
parison with other species or the study of buds in a more active state will 
be necessary to clear up this point. It is clear, however, that the slit repre- 
sents a shut-in portion of the external surface of the shoot, and the whole 
structure may be appropriately compared, as was done by Bower, to the 
sunken, shut-in, and often dormant buds of Equisetum . 
Four plants of Botrychium Lunaria , which bore developed branches, 
have been studied by means of successive transverse sections, and in another 
example the base of a lateral branch was seen in longitudinal section. In 
every case the apex of the main axis had been destroyed, and at a greater 
or less distance behind it a vestigial bud had developed to produce a branch, 
by means of which the growth of the plant was carried on ; in one specimen 
two vestigial buds had thus been developed. In the example of a lateral 
branch described and figured by Holle, the vascular supply was derived 
from the adaxial side of the leaf-trace and not from the stele of the main 
stem. The general position of all the branches I have studied agrees with 
this, but their vascular connexions exhibit differences of detail which make 
it necessary to describe all the examples. The variations found are of 
