Morphological studies on the genusClematis Linn

The basic pattern of the vascular supply to stamens and carpels in the flowers ofClematis is discussed on the basis of serial sections. The bundles of the receptacular stele show fairly regular fusions and divisions in relation to the origin of the vascular supply, giving off a single trace for each stamen or carpel. In many cases the trace arises by the trifurcation of the “fused bundle” and the subsequent departure of the median strand. This is the pattern basic to the structure of the receptacular stele of the genus. Although the basic pattern involves a variety of modifications, each of the diverging traces fundamentally leaves a single independent gap in the stele, contrary to the conclusion of previous authors. Similarities and differences between a group of stamens and carpels and that of sepals and foliage leaves are also discussed based on the results of the present and previous studies on the vascular anatomy of the floral receptacle and the inflorescence axis.