Jeffrey and Torrey . — Transitional Herbaceous Dicotyledons . 247 
Summary. 
1. The origin of the herbaceous type in the Dicotyledons is from 
woody or arboreal forms. 
2. Woody herbs, as a consequence, throw clear light on the mode in 
which the herbaceous Dicotyledons have been derived. 
3. In the aerial axes of woody herbs a constant and practically never- 
failing distinction from trees is the formation of large foliar storage rays 
about the incoming leaf-traces, as they pass through the woody cylinder. 
4. In woody herbs the foliar storage rays are well developed in the 
radial direction, but their vertical extension is slight. 
5. In the aerial stems of more slender and less woody Dicotyledonous 
herbs the foliar rays become elongated vertically to compensate for their 
reduced radial dimension resulting from the thinning down of the woody 
cylinder. 
6. In rays of the type described in 5, the lower part of the radial 
parenchyma related to the foliar trace is often bifurcated by a tongue of 
unmodified wood. 
7. The vertical elongation of the foliar rays and their subdivision in 
the manner described in 6 result in the final separation of the originally 
continuous woody cylinder into a series of separate strands. 
8. - The final stage of the herbaceous Dicotyledons is a condition in 
which the cylinder is thinned to such a degree that the radial extension of 
the foliar rays is virtually eliminated. With this condition is usually 
associated a great development in length of the portions of the foliar ray 
flanking the leaf-trace on either side. 
9. Recent statements asserting the absence of foliar rays in the aerial 
axis of the herbaceous type in the Dicotyledons are inaccurate. 
Literature cited. 
1. Eames, A. J. : The Herbaceous Type in the Angiosperms. Ann. Bot., vol. xxv, No. 97, Jan. 
1911. 
2. Bailey, I. W., and Sinnott, E. W. : The Origin and Dispersal of Herbaceous Angiosperms. 
Ann. Bot., vol. xxviii, No. 112, Oct. 1914. 
3. Jeffrey, E. C. : The Anatomy of Woody Plants. University of Chicago Press, 1917. 
4. Whitaker, Edith S. : The Anatomy of Certain Golden-rods. Bot. Gaz., vol. lxv, No. 3, 
March, 1918. 
