442 BOTANICAL GAZETTE [JUNE 
the study of this and other species of Potentilla. From the mode 
of perforations found in Pofentilla it is seen that both the scalari- 
form type and the Gnetum-like type, resulting from haphazard 
fusion, occur side by side and sometimes in the same species. 
It thus appears that both Ephedra and Gnetum-like types of per- 
foration occur in this instance, and undoubtedly the bordered open 
pore has originated here from the grouped pits, either by horizontal 
or haphazard fusions. The possession of the scalariform type of 
perforation thus loses significance as a phylogenetic criterion and - 
has only the importance of an anatomical detail. Further, the 
open bordered pore has often the same derivation in Potentilla 
and in other herbaceous Rosaceae as the similar bordered pore in 
Gnetum. 
We pass now to the Geraniales, a group systematically remote 
from the Rosaceae. Fig. 16 shows a longitudinal section of the 
wood of Pelargonium. In the center is the region of perforation of 
a vessel, showing the bordered pore typical of the more advanced 
species of Gnetum. Even the border is clearly evident, a condition 
which THompson apparently has failed to observe as occurring in 
the so-called porous perforation characteristic of the vessels of 
many Angiosperms, particularly (although not exclusively) those 
of herbaceous and liana-like habit. Fig. 17 shows another vessel 
of Pelargonium which illustrates an Ephedra-like perforation in 
this genus. There is obviously no difference here from the vessel 
perforation found in Ephedra except that the pits are small and 
both torus and membrane are always absent. There is no reason 
to believe that these pits are to fuse to form scalariform perforations, 
rather there is every evidence to infer a prospective haphazard 
fusion from the two or three instances of union manifested along 
the lower border of the perforation. This type precedes the open 
pore of fig. 16. Additional proof of this conclusion is supplied in 
fig. 18 from the same genus (Pelargonium). The vessel to the 
left has an interesting perforation. Small pits in the process of 
fusion surround an open bordered pore. When fusion is complete 
the enlargement of the central bordered porous opening will result. 
In the vessel adjacent to this is the large open bordered pore 
characteristic of the vessels of the Geraniales, and below it is 
