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the Sporophylls of the Cycadaceae. 
C. Miqueliana , H. Wendl., ? : row of three to four bundles 
in stalk, of which two lateral are of great size compared 
with the others ; along with largely developed centri- 
fugal, few small centripetal tracheides usually present, 
as is also the case with smaller bundles ; other 
smaller bundles, quite apart from normal row, with 
either normal or inverted orientation. 
The more general characters of the sporophyll are the 
following : — 
Male. A single bundle leaves the cylinder of the axis of 
the cone, which, on entering the stalk of the sporophyll, 
divides into three The bundles supplying the sporangia are 
much smaller in size than the similar ones on the female side, 
owing to the comparatively brief period of attachment to the 
sporophyll of the microsporangia and the short functional 
activity of the latter. They also diverge less from the 
mesarch structure of those of the foliage-leaf than do the 
bundles of the female sporophyll. 
Female. Two bundles leave the cylinder of the axis of the 
cone, usually dividing up in the cortex into a larger number, 
so that, as a rule, four bundles occur in the stalk of the 
sporophyll, of which the two lateral ones are much larger 
than the rest, this being correlated with their function of 
supplying the megasporangia during the long period of 
development and attachment of the latter to the sporophyll. 
The divergence from the ordinary mesarch structure of the 
foliage-leaf is much more marked here. 
In the sterile portion of the sporophyll of both sexes, i. e. 
the part above the insertion of the sporangia, the mesarch 
structure of the bundles prevails, showing how, the sporangial 
element being eliminated, the ordinary and typical structure 
of foliar bundles reappears. As compared with the bundles 
of the stalk, the centripetal is as a rule much more developed 
than the centrifugal xylem, while the phloem, which shares 
the development of the centrifugal xylem in the stalk, becomes 
reduced and insignificant. 
