Relation of Pteridosperm A natomy to that of Cycads. 63 
With regard to Worsdell’s second point—a consideration of 
the flowering axis of recent Cycads:—In the upper part of the 
peduncle of Stangeria, the vascular bundles become very irregularly 
orientated; some are more or less curved or even concentric. 
Worsdell considers that these bundles are the result of fragmen¬ 
tation of two or three sinuous steles, such as those of Medullosa 
Leuckarti (Fig. 17) ; the type of stele in M. Solinsii would represent 
an intermediate stage in fragmentation. Further, the centripetal 
Fio. 17.—A, Stangeria paradoxa. Transverse section of lower region of 
peduncle, showing irregular orientation of bundles. (Adapted from Worsdell, 
1906, after Scott), cf. Medullosa Leuckarti. 
B, Medullosa Leuckarti. Transverse section of tbe vascular system of the 
stem, schematically drawn to represent how the vascular system of Stangeria 
could have been derived by fragmentation of the large irregularly-shaped steles, 
the dotted lines representing the eliminated portions. (Adapted from Worsdell, 
1906). 
