444 BOTANICAL GAZETTE [JUNE 
It seems unnecessary to exemplify further the occurrence of 
perforations identical with those characteristic of the Gnetales in 
the Angiosperms, since the examples furnished, which could be 
indefinitely multiplied, show that the vessels of Angiosperms can 
and often do originate precisely as in the highest group of the 
perms, the Gnetales. It accordingly appears clear that 
THOMPSON’s assumption of a distinct origin for the Gnetales on 
the basis of a different mode of derivation of their vessels falls 
to the ground. This author has pointed out that the types of 
rays found in the Gnetales are strikingly similar in their mode of 
origin to those of the Angiosperms. He has further recently drawn 
attention to the nuclear fusions in the embryo sac of Gnetum, which 
he compares with the well known nuclear fusions in the female 
gametophyte of Angiosperms. It would appear, therefore, that 
far from demonstrating by his description of the mode of origin 
of vessels in Gnetum the separate derivation of the Angiosperms 
from the Gnetales, in reality this author has furnished additional 
conclusive evidence of their descent from a common stock. It is 
apparently clear from the present investigation that many herba- 
ceous and vinelike Angiosperms, from the lowest to the highest 
groups, show types of vessel perforation identical with those found 
in the usually vinelike Gnetum. Even the Monocotyledons manifest 
very commonly the Guetwm type of vessel, which is further quite 
universal in the Compositae. 
Summary 
1. Vessels with scalariform perforations of the angiospermous 
type and bordered porous perforations of the Gnetum type occur 
side by side in the Rosaceae, being found even in the same species 
of Potentilla. 
2. Similar observations are recorded for the Geraniales and 
Ranunculaceae, and these might be indefinitely multiplied from 
other herbaceous Angiosperms. 
3. Recent statements that the types of vessels in the Gnetales 
and Angiosperms are distinct in their mode of derivation are 
accordingly without foundation in fact. 
HARVARD UNIVERSITY 
