PEOFESSOE HENEEET ON THE ANATOMY OF VICTOEIA EEOIA. 487 
work of the excavated structure of the rind"^. As the stipules enlarge, they overlap 
their neighbours to some extent. The left-hand half of each double stipule lies over 
the outside of the right-hand half of the one older than itself, and its right-hand half 
is in tmn overlapped by the left-hand half of its successor ; as this right-hand half has 
the flower-bud in its axil, the latter becomes furnished with a double covering, which, 
as the stipules converge inward above, completely encloses and protects the flower-bud 
until it is pushed out by the elongation of the peduncle. The general character of the 
stipules is shown in the dravmigs. Each apparently axillary stipule is distinctly double, 
and the two halves are, when mature, connected by a membranous plate running across 
the axil, which base is quite unconnected with the base of the petiole (Plate XXVIII. 
fig. 3). Each half of the compound stipule has a very distinct midrib, which forms an 
angular projection in the earlier, more folded state of the organ. It was stated in the 
former paper that the spiral-fibrous structure soon disappears in the ducts and vessels 
of the leaf-stalks. This is not the case in the stipules, which exhibit perfect vessels 
when fully developed. 
To this paper are appended some illustrations of the elementary structure of the 
petioles and of the arrangement of the tissues, which do not require further notice here 
(Plate XXXII. figs. 69-61). 
The external aspect of the stem is rendered somewhat peculiar by the mode of 
arrangement of the roots, which arise in dense tufts or bundles at the bases of the 
petioles. The manner in which they emerge from the stem is highly curious, and 
unlike any other case with which I am acquainted. 
The roots are adventitious, and arise in the peripheral part of the central substance 
of the stem, just below where the fibro-vascular bundles run out to the petioles. No 
trace of the roots is visible externally until the leaves, especially the petioles, have 
acquired considerable dimensions (Plate XXVIII. fig. 4) ; then it is observed that the 
cortical substance of the stem is protruded so as to form a kind of knob at the base of 
the leaf-stalk ; or perhaps it may be best described by comparing it with a highly- 
protruding under the point of origin of the leaf-stalk (Plate XXIX. fig. 8). 
Ultimately a vertical fissure is perceived in the protuberance, the sides of which gradu- 
ally separate, with rounded edges like lips, leaving an elongated elliptical slit, at the 
bottom of which are seen the points of the nascent roots (figs. II, 12). The roots, 
densely crowded, make their way out, the oldest at the lowest part, and they are given 
out in such rapid succession that they form a close bunch. As they emerge and expand, 
they convert the vertical slit into a large rounded bordered orifice (figs. 15, 16). During 
the subsequent growth of the roots, the protuberance keeps firm and forms a large pro- 
jecting knob ; but their mutual pressure gives the bases of the roots an angular form, so 
that when they become detached on the decaying parts of the stem, their ends form the 
six-sided areolae shown in the illustration of my former paper. 
It has been noticed above that even the earliest roots, the bundles of which consist 
* Philosophical Transactions, 1852, Plate XIX.//. 
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