CYCADALES 



131 



character prevails; but in the rather feebly developed bundles of the 

 inner set of strands of the ovule it is not always easy to distinguish 

 the protoxylem. These weaker bundles are collateral, with but 



128 



129 



Figs. 128-131. — Diagrams of course of vascular bundles in sporophyll and ovule: 

 fig. 128, Encephalartos villosus, course of bundles in megasporophyll; o, cf, </', three 

 bundles passing to the ovule; fig. 129, small portion of the upper part of the ovule 

 on a larger scale; fig. 130, Microcycas calocoma, vascular supply of ovule and sporo- 

 phyll; fig. 131, Ceratozamia mexicana, vascular supply of ovule and sporophyll. — 

 After Matte (40). 



little phloem, and when mesarch the development of centripetal 

 xylem is very slight. The large central bundle, which in Cycas 

 and some other genera gives rise to most of the inner set of vascular 

 strands, is concentric or nearly so. 



