228 Jeffrey and Torrey.— Transitional Herbaceous Dicotyledons . 
strongest evidence in its support, are found not in the aerial parts of the 
stem but in the underground portions l Further, ‘ The fact that intermediate 
stages in harmony with the theory we are criticizing are so rare in aerial 
stems as to be regarded as one of its weak points ’. In a following paragraph 
the authors under review state, ‘ The fact, however, which militates most 
strongly against the validity of the hypothesis under discussion is that, in 
practically all many-bundled herbaceous stems, the interfascicular paren- 
chyma is not subtended by tiny leaf-trace bundles, nor is the stem composed 
of presumably typical alternating large and small bundles, the latter being 
leaf-traces.’ 
It will be shown in the sequel that Messrs. Bailey and Sinnott are 
apparently ignorant of fundamental facts in regard to the organization 
of the aerial stem in herbs. Further, they fail to distinguish the modifica- 
tions in the general topography of the axis resulting from the different 
degrees of advance towards the herbaceous condition, thus showing a singular 
lack of capacity for thinking in three dimensions. The erroneousness of 
their statements will, moreover, be demonstrated on the identical forms 
which they present as evidence for the truth of their views. In advance, 
this general criticism must be made of their illustrations and their deduc- 
tions. They fail to realize that if there is such a thing as a leaf-ray, it would 
naturally occur in the nodal region of the stem, where the traces enter the 
axial organ. Their illustrations throughout show a surprising inability to 
grasp this rudimentary principle of anatomy. 
Obviously a clear conception of the differences of anatomical organiza- 
tion between a woody and an herbaceous stem can best be obtained by 
comparing the nodal regions of nearly related trees and herbs. The authors 
under discussion have figured Hibiscus and Abutilon as examples of 
herbaceous types. It may quite reasonably be urged that neither of these 
genera, which are of tropical or sub-tropical distribution, can be regarded as 
typical herbs, particularly by our authors ; for in the later pages of their 
article they have elaborated at great length the hypothesis (which however 
did not originate with them) of the temperate distribution of characteristic 
herbs. Since both Abutilon and Hibiscus are distinctly woody and tropical 
herbs, they obviously will supply the supreme test of the correctness of this 
hypothesis, emphasizing the development of foliar rays as a fundamental 
feature of distinction between trees and herbs. 
Fig. i, PI. XI, shows the general organization of a year-old stem of the 
common Basswood (Tilia sp.), or Linden, as an example of the nodal con- 
ditions in an arboreal representative of the Malvales. On either side of the 
long axis of the pith is to be seen a depression in the inner contour of the 
woody cylinder, marking the situation of a foliar trace, which has just 
entered the axis at the node above. In Fig. 2 a part of Fig. 1 is shown under 
a higher degree of magnification. The foliar trace lying in its internal 
