1921] MacCDUFFIE—V ESSELS 443 
another similar perforation. Fig. 19 shows a higher magnification 
of the same vessel as presented in fig. 18. The details of border 
in the large central pore demonstrate the existence in Angiosperms 
of the Gnetum-like pore. Fig. 20 illustrates another vessel of 
Pelargonium showing two perforations in series. The upper 
perforation manifests a transitional stage of fusion. The high 
degree of magnification furnishes undoubted evidence that the 
complete fusion of pits will result in a large bordered perforation 
precisely as in Gnuetum. Below is a bordered porous perforation. 
Fig. 21 shows the partially pitted perforation of another vessel 
of Pelargonium. Fusion for the most part has already taken 
place, but enough small pits remain to establish a definite origin 
of the open bordered pore by Gnetum-like haphazard fusion. 
Fig. 22 shows a scalariform perforation in the same species of 
Pelargonium. The existence of this type, together with the 
bordered perforation derived from the fusion of Ephedra-like 
terminal pits, illustrated in the Rosaceae, shows again that the 
scalariform type of perforation is not exclusively present in or 
solely characteristic of Angiosperms. There is undoubted similarity 
between perforations of the Rosaceae and the Geraniales and those 
obtaining in Gnetum itself. 
Fig. 23 shows two interesting vessels of the wood of Tropaeolum 
as a further illustration of the Geraniales. Both vessels have the 
Ephedra-like grouping of pits, although the size is obviously 
smaller than in that genus. Close scrutiny reveals the fusion to 
be haphazard-oblique and marginal, and not resulting in horizontal 
scalariform perforations. Most of the vessels in Tropaeolum have 
the Gnetum-like bordered terminal pore. Fig. 24 shows a section 
through the wood of Clematis species, an example of the Ran- 
unculaceae. The margin of an open bordered perforation is shown, 
and around its inner edge is seen a fringe of haphazardly fusing pits. 
Vessels of the Guetum type are practically universal in the Ran- 
unculaceae. 
Conclusions 
Conditions similar to those illustrated for the Rosaceae, Gerani- 
ales, and Ranunculaceae are widespread among dicotyledonous 
Angiosperms, particularly those of herbaceous and climbing habit. 
