Additional Notes upon the Angiosperms Tetracentron, 
Trochodendron, and Drimys, in which Vessels are 
absent from the Wood. 
BY 
I. W. BAILEY, 
Bussey Institution , 
AND 
W. P. THOMPSON, 
University of Saskatchewan . 
With Plate XVI and nine Figures in the Text. 
I N a paper read at the celebration of the twentieth anniversary of the 
New York Botanical Garden, September 1915, the writers ( 11 ) discussed 
the significance of certain features in the anatomy of Tetracentron , Trocho- 
dendron , and Drimys. It was shown that not only are true vessels entirely 
absent from the normal wood of the stem of these genera, but also from 
those organs or regions 1 that are considered by certain morphologists to be 
retentive of ancestral characters. 
The accuracy of the conclusions reached by the writers in regard to 
the absence of vessels in Tetracentron , Trochodendron , and Drimys has been 
brought into question by the work of Jeffrey and Cole (6). These investi¬ 
gators claim to have found vessel-like structures in injured roots of Drimys 
colorata , which abnormalities are considered to indicate that the ancestors 
of Drimys , Trochodendron , and Tetracentron possessed true vessels. 
However, it is admitted by Jeffrey and Cole that the elements, 
described and figured by them, lack the perforations of normal vessels. In 
view of this fact, it is desirable to determine to what extent these trauma- 
tically produced cells are really vessel-like in structure. 
The word vessel, which was used in a variety of meanings by the older 
phytotomists, was first clearly defined by von Mohl (8) in the middle of the 
last century. 
£ The primary form of the elementary organs of plants is that of a com¬ 
pletely closed, globular or elongated vesicle, composed of a solid membrane 
1 Root, leaf, node, floral axis, seedling, first annual ring, &c. 
[Annals of Botany, Vol. XXXII. No. CXXVIII. October, 1918.] 
