I920J 



DUPLER—TAXUS CANADENSIS 517 



supply arises equally from the two sides of the axis cylinder, the 

 entire cylinder being involved in the supply. The bundles as they 

 pair and fuse arise from opposite the second pair of scales and 

 alternate the third pair of scales, an anomalous situation if the 

 ovule were axillary to either of the third pair of scales. The ovule 

 bundle supply is a direct continuation of the axis cylinder, the 

 fusion of the bundles in the base of the aril closing the gap above the 

 second pair of scale bundles. The orientation of the bundles is 

 normal and presents no difficulty. The course of the bundles being 

 opposed to the idea of an axillary origin is also against the view 

 that there may have been a fusion of sporophyll with integument, 

 and that the integumentary bundle is a vestige of that fusion. 

 The presence of vascular bundles in the integument of gymnosperms 

 is sufficiently common to cause no surprise in such forms as the 

 taxads, nor is there any more argument for the sporophyll nature 

 of the integument there than there might be in the cycads, where 

 sporophyll and ovular integument are not confused, unless it be 

 necessary to supply a theoretical sporophyll for a terminal cauline 

 ovule. 



The terminal cauline nature of the ovule is a much simpler 

 interpretation of the facts, according both with the ontogenetic 

 origin and the vascular supply. While this is an unusual situation 

 for a gymnosperm, it is not out of harmony with a tendency 

 among the seed plants, a tendency expressing itself frequently in 

 angiosperms and not necessarily impossible in gymnosperms. 



Summary 



1. The ovuliferous bud arises in the axil of a leaf early in the 

 season, and matures the next year. 



2. The ovuliferous organ consists of the primary shoot and the 

 secondary shoot with the ovule. 



3. The primary shoot is to be regarded as a vegetative branch 

 of limited growth, bearing only reproductive axes (secondary 

 shoots). While of limited character, at times it may become a 

 functional vegetative shoot like any other vegetative branch. 



4. The primary shoot is a persistent structure, functional for 

 several successive seasons. 



