1921} JEFFREY & TORREY—HERBACEOUS ANGIOSPERMS 5 
the foliar rays of the species of Aster under consideration extend 
only a slight distance downward in their normal form, and as 
a consequence in the lower and stouter region of the part of the 
stem above ground usually only three typical leaf rays can be seen 
in a given plane of section. 
Fig. 2 shows a transverse view of the same Aster in the upper 
region of the aerial stem. Here the woody cylinder appears much 
thinner, in spite of the fact that the magnification is considerably 
higher than in fig. 1. A projection on the upper surface marks the 
position of the median trace of a leaf belonging to the nodal region 
from which the section has been made. The higher part of the 
stem, as is often the case in above ground herbaceous axes, shows 
the leaf traces and their corresponding foliar rays as projections 
from the surface of the woody cylinder, and not depressed, as is 
the normal condition for these structures in herbs of woody texture 
or in the woody lower region of the aerial stem of more typically 
herbaceous axes. In addition to the three projecting leaf traces 
and their corresponding foliar rays, which occupy adjacent positions 
on the upper surface of the woody cylinder in fig. 2, are to be seen 
5 or 6 less prominent traces and corresponding foliar rays belonging 
to leaves higher up on the stem. In figs. 3-5 is reproduced the whole 
of the woody cylinder of fig. 2, on a somewhat higher scale of 
magnification. It will be seen from figs. 2-5 that there are 8 
leaf traces clearly obvious, alternating with as many “common’”’ 
or “cauline” segments. This interesting situation results from 
the fact that in the upper more herbaceous region of the stem 
the foliar rays extend, as such, much deeper down than in the case 
of the lower woody region of the same aerial axis. Consequently 
a number of leaf rays corresponding to the traces of leaves at 
several nodes can be distinguished in a single transverse section 
through the higher region of the stem. Srmynort and BatrLey (5) 
have denied the possibility of the conditions represented in figs. 2-5. 
The topography in question is in fact extremely common in herbs 
of a certain degree of advance from the woody primitive an- 
cestral forms. Naturally it does not occur in extremely woody 
herbs, on the one hand, because in these very few foliar rays can 
usually be seen at one time, and these in rather close vertical 
