4O2 



THE ANATOMY OF WOODY PLANTS 



foliar strand projects beyond the surface of the cylinder and is 

 merely flanked and not subtended by storage parenchyma, as in 

 similar regions in other herbaceous stems of the most varied 

 affinities. In contrast, in Fig. 280, which is from a lower and 

 more woody node, a large amount of confronting storage tissue is 

 seen, as well as that present on the flanks of the trace. 



The topographi- 

 cal conditions in the 

 stem of Helianthus, 

 as representing a 

 high and typical 

 herbaceous condi- 

 tion, may now 

 advantageously be 

 depicted in stereo- 

 diagram. Fig. 28 la 

 reproduces the 

 lower portion of 

 the stem of Helian- 

 thus. The scar of 

 the leaf of one node 

 faces the observer, 

 while the region 

 just below the next 

 higher node is shown in transverse section. The six traces of 

 the two opposite leaves are clearly seen, and it can be readily 

 observed that they are both flanked and faced by storage tissue 

 (black). The very narrow deep bundles in the cross-sec don 

 represent leaf traces of the next higher node, while the light masses 

 on the periphery of the broad remaining strands indicate the 

 position of the fused foliar traces of a still higher node. In b 

 is shown (above) a radial and (below) a tangential view of the 

 topographical relations of the leaf traces in these planes. In 

 the upper figure of b there is obviously much storage tissue con- 

 fronting the trace. In the lower item the trace in tangential 

 section is seen entirely surrounded by storage tissue. Fig. 28 ic 

 is a picture of the solid relations of a higher part of the stem in 



FIG. 280. Section of trace in thick woody region of 

 Helianthus. 



