320 BOTANICAL GAZETTE [APRIL 
Passing to a consideration of a type of vessel in the Angiosperms 
which is characterized by porous and not scalariform perforations, 
and taking a form nearly allied to the Betulaceae, Quercus velutina, 
we invariably find in the mature wood porous perforations which 
in the smaller vessels sometimes show a border like that character- 
istic of similar perforations in Gnetum. SOLEREDER (4) has already 
pointed out in the oak and other representatives of the Fagaceae 
that scalariform perforations are characteristic of regions near the 
primary wood. I have been able to confirm this general statement 
of SOLEREDER in regard to the oak. A radial section of Quercus 
velutina (fig. 32) through the primary wood of the leaf trace shows 
a very interesting condition in the perforation. The transition 
from the pitted to the scalariform condition is very clear. Usually 
the perforations of the vessels in the primitive region of Quercus 
are scalariform only, without transition from the pitted condition. 
In Fagus one frequently finds vessels with scalariform perforations 
even in the mature wood. 
We may now consider the Rosaceae, a higher group, character- 
ized in general by porous perforations of the vessels. Taking first 
a herbaceous representative of the family, fig. 33 shows a vessel 
in the region of the primary wood of the stem of Potentilla 
monspeliensis, an annual herb. The vessels in this region 
have scalariform perforations which pass gradually, by the 
disappearance of transverse bars, into porous perforations. 
SOLEREDER has described a similar condition in Potentilla fruticosa, 
and it appears to be widespread in the genus. As a woody 
representative of the group, Cydonia is interesting as showing the 
scalariform perforation of the vessel in the region of the primary 
wood (fig. 34), as found in Potentilla. An interesting situation is 
presented by the organization of the vessel in the primitive 
region of the leaf trace, in its course in the stem of Cydonia 
japonica (fig.. 35), in which the perforation is pitted, a very 
significant condition. Taking the Rosaceae as illustrated by 
Potentilla and Cydonia, it seems clear that the porous condition 
of the perforation has been preceded by the scalariform, and the 
scalariform in turn by the pitted. 
