1921] JEFFREY & TORREY—HERBACEOUS ANGIOSPERMS *7 
These illustrations, which might be indefinitely multiplied 
from the nodes of herbaceous Dicotyledons, make it clear that 
amphivasal bundles resembling those of the Monocotyledons are 
frequently present in the nodal regions of dicotyledonous herbs, 
and result from the fusion of strands by their phloem faces. The 
similarity of the conditions in the two great divisions of the Angio- 
sperms may be confirmed by an illustration taken from the grasses. 
Fig. 39 shows the nodal region of the upper part of the aerial stem 
of Zea. A leaf base is uniting with the stem, and on the upper left 
the fusion of the foliar vascular supply with that of the axis is 
farther advanced than it is on the lower right side of the illustra- 
tion. This condition is due to the fact that either the section is 
not exactly transverse, or else the fusion of the leaf base is not 
effected in an exactly horizontal plane. It matters little which 
explanation be adopted. The bundles which enter the stem from 
the leaf are obviously extremely numerous, and their accommoda- 
tion in the stem is accordingly a matter of some complexity. The 
device by which their reception is effected is by means of fusions 
similar to but more complicated than those exemplified in the 
dicotyledonous types figured. Fig. 40 shows a part of the upper 
left hand portion of fig. 3:more highly magnified. Three amphivasal 
bundles can be seen forming an oblique line from the lower left 
to the upper right of the figure. Between these lie other bundles 
which are in the act of fusing. A characteristic feature of the 
nodes of the aerial stem of grasses, sedges, and rushes is the presence 
of amphivasal bundles in the region of the nodes, resulting from 
the fusions effected in connection with the entry of the numerous 
foliar bundles into the stem. In the mass of Monocotyledons 
these amphivasal fusions are no longer found in the often highly . 
specialized, annual, aerial axis, but are confined to the more primi- 
tive, perennial, subterranean stem. In the Scitamineae and true 
palms amphivasal bundles are usually entirely absent. 
We may now turn to further illustrations of the absence of 
cambial activity in foliar strands which have recently entered the 
stem in the dicotyledonous Angiosperms. The legumes are a very 
important family of Dicotyledons, which are represented in tem- 
perate regions by many herbaceous forms. Fig. 41 shows the 
