392 MISS M. G. SYKES ON THE SEEDLING AND 
of fibres are seen to be developing just internal to the epidermis (Pl. 34, fig. 10a), 
Higher still these fibres are fully mature (fig. 10 b): they are thick-walled unlignified 
cells, exactly resembling those borne in groups under the epidermis of the leaf 
in Welwitschia and occurring in many other parts of the plant. A few lignified 
elements occur on the outer edge of some of the groups of fibres, chiefly at the ends of 
the oval, but it is not possible to affirm that these are of the nature of xylem and they 
were lignified only for a very short part of their course (fig. 10 a, L). The upper part 
of the object is composed entirely of loose corky cells with suberized walls, and 
there can be little doubt that it is in a degenerating condition. 
It may be that the structure is to be regarded as axial in nature, produced by the 
further development of the apex itself. I am more inclined to consider it as repre- 
senting another pair of leaves fused by their contiguous surfaces and never having 
attained to mature development. This possibility was suggested to me by an exami- 
nation of the seedling shown in fig. 6, in which the first two plumular leaves were still 
contiguous by their inner and upper surfaces, and the hypothesis is supported by the 
presence of regular peripheral groups of fibres, but there is no trace of a double origin *. 
The parenchymatous nature of the base is probably evidence that it has been added to 
in that region by meristematie growth, as is the case with the leaves. It would certainly 
appear that the apex of the structure is older than the base. 
A very remarkable development of one of the leaves of a young plant is to be seen 
in fig. 8a, b. While one of the leaves was normally developed from the groove on one 
side of the plant, the other was only partially confined to the groove on the other side. 
Half of its width originated from half of the groove, but its other half from a deep 
groove between the free cotyledonary buds, leaving unoccupied the other half of the 
normal groove. It was considerably torn, and from its position was at first taken for an 
extra leaf such as that shown in text-fig. 1. That part of the inner ridge which 
surrounded the cotyledonary bud encircled on two sides by the leaf in this abnormal 
fashion was unusually well-developed and zoned; meristematic division had evidently 
been very active there. On the outer side of the leaf a small extra lobe (B 3) was also 
present and another lobe, not shown in the figure, occurs at B 4. 
A transverse section through the hypocotyl (of the specimen represented in fig. 8) at 
the level of entry of the leaf-bundles shows a straight row of bundles entering from 
one leaf, and an L-shaped series from the other, the hook of the L passing between the 
bases of the two main buds (Pl. 35. fig. 23). 
The fact that half of one side of the “ leaf-groove ” is here unoccupied by a leaf 
appears to me to be a fact of some interest. It makes more evident the independent 
growth of the two ridges (the two lips of the groove), a fact more surprising here than 1? 
the normal plant, where they are separated from one another by the base of the leaf. 
The presence of extra lobes to the crown was found in one other case besides 
that recorded above. In this example one lobe was divided into three (fig: 9) bi 
* : E " à 5 uh r 
It is also interesting to notice that this seedling, like the one with the extra leaf, was found by Professo 
: Ne i th. 
— Mossamedes, a comparatively damp district, in which Welwitschia manifests unusually active grow 
ea 
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(un 
x A 
b 
© 
