Scott. — On Peduncle of Cycadaceae. 407 
Vascidar System. Before leaving Stangeria certain other 
peculiarities of the vascular system in the peduncle must be 
considered. 
Throughout the whole length of the organ the main 
bundles fuse and separate again repeatedly, forming collect- 
ively a hollow network, with long meshes, as described by 
Count Solms-Laubach 1 . The number of the strands, as seen 
in transverse section, thus remains approximately constant, 
except at the base of the peduncle and the apex of the cone, 
where it diminishes greatly. In the lower part of the peduncle, 
where the ring of bundles becomes flattened and contracted, 
every kind of irregularity in their arrangement and orientation 
may be observed (see Fig. 2) 2 . 
Often the xylem forms a horse-shoe, opening inwards, with 
the phloem in its convex side (see Fig. 2, strand 4). In other 
cases two bundles lie close together with their phloem-masses 
in contact (Fig. 2, strands 1, 1). Comparison of successive 
transverse sections shows that the former arrangement is due 
to the fusion of two bundles from above downwards, while the 
latter case indicates that two bundles are about to fuse from 
below upwards. Occasionally the horse- shoe form becomes 
exaggerated, so that the xylem appears as a ring, nearly or 
quite surrounded by phloem. In fact a concentric structure 
may be acquired for the moment, but this peculiarity is quite 
local, and dependent simply on the fusion of the bundles ; no 
morphological importance can, I think, be attached to it. 
At a still lower level in the peduncle all the irregularities 
again disappear ; the bundles, reduced in number, once more 
form a perfectly regular ring of small size, with typically 
collateral structure and normal orientation. The abnormalities 
of the transitional region are probably due to mechanical 
causes, the tissues developing under pressure from the leaf- 
bases, between which this part of the peduncle is wedged in. 
On the other hand the small cortical strands which occur 
in the peduncle, especially in its lower part, present some 
1 Sprossfolge der Stangeria, p. 213. 
2 Cf. Solms-Laubach, 1 . c. p. 212. 
