580 ‘ ¥F, 0. BOWER. 
position to the original lobes ; but in plants above this size this 
character is usually lost, since the comparatively small fissure 
which marks off the two areas from one another is masked by 
the much more deep fissure of the crown, which, as described by 
Hooker (l.c., p. $), runs in a direction paralle] to the bases of the 
plumular leaves of old plants. In all plants, however, of suitable 
age which have passed through my hands, the same conforma- 
tion appears between the plumular leaves. We may then con- 
clude that the apical cone of Welwitschia ceases to grow either 
apically or laterally, and that the crown is derived directly and 
solely from two lateral cones arising on either side of the apical 
cone between the plumular leaves; further, that these maintain 
a constant increase in width throughout the life of the plant. 
The question naturally arises, what is the morphological value 
of the two lateral cones? I conclude, on the following grounds, 
that they are morphologically axillary buds in the axils of the 
cotyledons. 
(a) Their position supports this view, if allowance be made for 
lateral compression by the plumular leaves, to the development 
of which every part of the plant seems to be subordinate. The 
lateral cones do not appear to be genetically connected with the 
apical cone of the plant. 
(4) Such axillary buds are to be found in the axils of the 
cotyledons of Ephedra. 
(c) Their structure, when older, has very little resemblance to 
a leaf (the alternative view being that they are a second pair of 
plumular leaves). 
(d) The development of axillary buds is the rule in the fertile 
branches of Welwitschia, and this occurs in the axils of the jirst 
pair of leaves of the male branch. 
The position of the leaves and their insertion at the base of 
the leaf grooves are facts already so well known that they need 
hardly be again described. Reference need only be made to 
figs. 111 and vii, in which the well-known arrangement will be 
easily recognised. 
Hypocotyledonary Stem and Apical Region.—Internal Structure. 
We shall now be in a position to continue the study of the 
course pursued by the vascular bundles as they proceed up the 
hypocotyledonary stem. We have seen the central bundles 
arrange themselves round four centres (fig. v1, 4), while in the 
peripheral part of the section appear a number of small bundles, 
which anastomose freely both with one another and with the 
' As a parallel case to this is cited by Mr. W. T. Thiselton Dyer 
Mora excelsa of British Guiana. | 
