238 Jeffrey and Torrey . — Transitional Herbaceous Dicotyledons . 
foliar rays may be short, while the radial development is often prominent. 
In the upper slender portion of the same axis, on the other hand, the rays 
are frequently shallow radially and vertically extremely elongated. 
In Text-fig. 2 are elucidated, in respectively more and less herbaceous 
species of Clematis , the topographical relations of the foliar rays. The 
Text-fig. i. Centre diagram of the woody genus Baccharis. Left, tangential view of the si 
node of Helianthus . Right, tangential view of the nodal region of Bidens. 
diagram to the left shows a somewhat woody species. There are six foliar 
traces projecting somewhat into the medullary region, to which are related 
radially six corresponding foliar rays. The storage tissue in these rays is 
mainly exterior to the foliar traces, but some of it lies on their flanks. In the 
right-hand figure an herbaceous species of Clematis is represented. Here the 
