Some Features of the Anatomy of the Vitaceae * 1 
BY 
JUNE ADKINSON, A.M. 
Radcliffe College. 
With Plate XV. 
HE wood structure of Vitis, distinguished by large vessels, broad rays, 
X and septate tracheides, has been cited, together with that of Aristolochia 
and Clematis , in support of the theory that the woody cylinder of plants is 
derived by the coalescence of a ring of originally separate fibro-vascular 
bundles. The broad rays were called the c primary ’ rays because they were 
supposed to be formed from fundamental tissue between the primary 
bundles. Later other rays, frequently linear, appeared in the segments 
of the wood, while at the same time the fascicular cambium extended 
across the broad rays and began to lay down secondary tissues between the 
primary bundles. In this manner secondary growth of the stem proceeded. 
According to this view, the herbaceous stem, characteristic of primitive 
plants, has given rise to the woody cylinder increasing by secondary growth 
in perennial forms. If this be the true order of development, Vitis is inter- 
mediate in structure between the herb and the tree. 
By evidence gathered in recent investigation, this hypothesis of the 
origin of the woody cylinder and of the herbaceous stem has been replaced 
by another which seems more accurately to explain the facts. In both 
Lycopsida and Pteropsida, in both vascular cryptogams and seed plants, the 
herbaceous type of stem has proved itself to be more persistent and better 
adapted to modern conditions of climate . 2 By the work of Bailey 3 and 
Eames , 4 on both anatomical and palaeontological evidence, the broad ray 
of Quercus is known to have developed by aggregation and final compound- 
1 Contributions from the Phanerogamic Laboratories of Harvard University, No. 54. 
2 Eames, A. J. : On the Origin of the Herbaceous Type in the Angiospermae. Annals of 
Botany, vol. xxv, No. xcvii, p. 215. 
3 Bailey, I. W. : Reversionary Characters of Traumatic Oak Woods. Botanical Gazette, 
1» PP- 374-8°. No. 5. 
4 Eames, A. J. : On the Origin of the Broad Ray in Quercus . Botanical Gazette, xlix, 
No. 3. 
[Annals of Botany, Vol. XXVII. No. CV. January, 1913.] 
