310 BOTANICAL GAZETTE [october 



that the final destination of a bundle does not always determine to 

 which sporophyll part it belongs. It is to be suspected that the 

 bundle system of Agathis and Araucaria represents a complex of 

 bract and scale bundles. Judging by the course of events in 

 other conifers with single-veined vegetative leaves, it may be 

 suggested that the large median lower bundle in Cunninghamia 

 David iana is the bract bundle proper, which is accompanied 

 for some distance into the free portion of the bract by a few scale 

 bundles. 



Taxus presents some features which perhaps ought to be men- 

 tioned. The single ovule is produced terminally on a secondary 

 dwarf branch clothed with a few pairs of decussate bracts. The 

 primary dwarf branch may occasionally become a long branch by 

 the resumption of growth by its terminal bud. In all of the many 

 ovules examined the ovule is flattened transversely to the upper- 

 most pair of bracts. The four final bundles of the branch of the 

 axis which fuse in pairs before entering the two wings of the ovule 

 fuse in pairs across the next lower pair of bracts, and not across the 

 uppermost pair of bracts, a behavior which is contrary to what 

 should be expected if the fused bundle were destined to supply an 

 axillary structure. The dying out of bundles near the tip of the 

 axis and the consequent failure to supply the uppermost bracts or 

 enter into the formation of the ovuliferous supplies, as the case may 

 be, suggest that a general reduction and loss of parts is taking 

 place. The terminal position of the ovule, the flattening of the 

 ovule transversely to the uppermost bracts, and the fusion in pairs 

 of the final bundles of the axis in the definite way to form the two 

 bundles of the wings of the ovule suggest a structure which might 

 result from a process well under way in Juniperus communis, 

 namely the fusion of sporophylls to form a single structure. This 

 in Taxus would imply the reduction of the ovules to one, the com- 

 plete fusion of two sporophylls to the integument of the ovule, and 

 finally the reduction of the vascular supply of each sporophyll to 

 the single weak bundle present in the wing of the ovule. In view 

 of the modifications that are apparently taking place in other coni- 

 fers such a course of events may be possible, hut further 

 investigation is necessary. 



