Jeffry and Torrey . — Transitional Herbaceous Dicotyledons. 235 
the left, lies the radial aspect of the entirely parenchymatous foliar ray. To 
the right of the leaf-trace is shown the darker-hued parenchymatous 
material, which represents the soft matrix occupying the leaf-gap. The 
three figures described above give an accurate view in three dimensions of 
the foliar ray as it appears in the Golden-rod. The topography of the 
foliar rays is surprisingly uniform in the Compositae, and literally hundreds 
of instances could be furnished for illustration, exactly paralleling those 
shown in Figs. 28, 29, and 30. Figs. 31 and 32, PI. XIII, show tangential 
views of the foliar rays in two different species of Sunflower. In Fig. 31 is 
revealed the tangential aspect of the leaf-ray in Helianthus Uiberosus , a 
perennial species with annual aerial stems. In the substance of the leaf-ray 
in this species even the low power of magnification used reveals the presence 
of other than parenchymatous elements. In other words, the ray is of mixed 
constitution and still contains some of the vessels and fibres of the wood 
from which it was originally formed. In Fig. 32, PL XIII, is revealed, under 
the same degree of magnification as in the preceding figure, the foliar ray 
of the strictly annual species Helianthus annuus. The very much larger size 
of both foliar ray and its corresponding foliar trace are easily observed. 
The difference in dimensions observed corresponds closely with the degree 
of herbaceousness in the two species. Helianthus annuus is large, vigorous, 
and very herbaceous, and is able to go from seed to seed in a comparatively 
few weeks. Another feature of interest from the comparative standpoint, 
other than the greater development of both leaf-trace and the corresponding 
foliar ray in H. annuus , is the homogeneity of the ray itself, indicating 
a more advanced degree of transformation from the original wood into 
storage tissue. 
In the foregoing paragraphs and their accompanying photographic 
illustrations a considerable variety of evidence has been supplied in support 
of the proposition advanced from these laboratories some years ago, that 
herbaceous stems, in their origin at any rate, are characterized by the 
presence of large foliar rays, radially subtending the foliar traces. It should 
be emphasized that the figures are only illustrative of an infinitely larger 
number of facts of a similar character, as it is obviously impossible within 
the limits imposed by an article in a scientific magazine to describe or cite 
in detail more than a comparatively few cases bearing upon the theme under 
discussion. An attempt has, however, been made to have the illustrations 
chosen thoroughly representative of the course of evolution of herbs from 
woody ancestors. In a good number of instances the woody or arboreal 
type has been figured in proximity to its herbaceous derivative so that easy 
comparison of the two is possible. The present authors are of the opinion 
that, with these illustrations before his eyes, no competent and fair-minded 
reader can deny the existence in typical Dicotyledonous herbs of the 
structures which we have called foliar rays. It will further be clear to those 
