228 WorsdelL — The Vascular Structure of 
cases the appearance is as if two distinct bundles were 
closely united, but not completely fused, by their ventral 
faces ; in others the bundle has a curved, or horse-shoe shape. 
The bundles are all irregularly orientated, mostly assuming 
a sidelong position (Fig. 22). But these structures are of 
importance from the fact that they exhibit more primitive 
characters than the bundles of the fertile sporophyll, the 
latter differing entirely therefrom, both in structure and 
arrangement, being perfectly collateral and normally orien- 
tated. It is owing to the absence of the sporangiferous 
function in these barren sporophylls that this primitive 
structure has been retained. 
ZAMIA LODDIGESII, Miq. 
Female Sporophyll. Two bundles leave the cylinder of 
the axis of the female cone, each from a distinct strand 
thereof. On their way through the cortex each divides into 
two, thus forming four bundles. The small bundles which 
occur in pairs in the cortex of the peduncle and which 
supply the barren sporophylls at the base of the cone have, 
many of them, centripetal xylem, of the normal kind and 
in the form of very distinct transfusion-tissue, both in a 
ventral and a lateral position (Fig. 24). 
Of the four bundles in the stalk of the sporophyll, the 
smaller, newly-formed ones move somewhat forward towards 
what becomes the ventral side of the organ. The two lateral 
bundles are somewhat larger, though not so strikingly so as 
in other genera. All these bundles have several elements of 
centripetal xylem which are often larger than the tracheides 
of the centrifugal portion ; in this respect this plant affords 
quite an exception to the general rule. 
One bundle turns off to the megasporangium on each side, 
dividing into two main branches ; one of these, the proximal 
one, before entering the sporangium, divides in different 
directions into three branches ; the distal bundle, which 
