318 BOTANICAL GAZETTE [APRIL 
a condition practically identical with a similar section of the root of 
Liriodendron as seen in fig. 18. Fig. 22 illustrates the character 
of the vessel in the first annual ring of a branch of Magnolia 
Frazeri. The perforation is obviously scalariform, while the lateral 
wall is characterized by typical pits. The end wall perforations 
again show evidence of fusion of pits in the “ghosts”’ and indenta- 
tions on the scalariform openings. In many instances scalariform 
perforations may be seen to grade into pits in the wood of the stem 
of Magnolia Frazeri. It seems clear from a study of the primary 
wood region of the root of Liriodendron and Magnolia that the 
vessel with pitted walls is antecedent to the vessel with scalariform 
walls, and further that the scalariform perforations which are uni- 
versal in the vessels of Liriodendron Tulipifera and are like- 
wise found frequently in the vessels of species of Magnolia 
are the result of fusions of pits precisely as in the case of the 
perforations of the vessels of Gnetum and Welwitschia in Gne- 
tales. Since evidence from primitive regions in Gnetales has been 
used by THompson (6) in tracing the origin of the perforations in 
vessels of that group, the validity of a similar procedure as regards 
the evidence in the Magnoliaceae obviously must be admitted. 
As another representative of the Ranales, the ranunculaceous 
genus Paeonia is interesting as showing in the vessels of the stem 
typical scalariform perforations (fig. 23). This observation 
confirms SOLEREDER’S (4) statement that “only simple perforations 
have been observed in the woody and herbaceous genera of this 
group with the single exception of Paeonia.’’ In the leaf trace of 
a species of Paeonia (figs. 24, 25) in the region of the primary wood, 
the perforations show the more primitive pitted condition combined 
more or less with the more modern scalariform condition. The 
protoxylem elements are visible at the left of the figures, and here 
again in close proximity to the primary wood (fig. 25) we have the 
vessel with the pitted side wall. 
The Betulaceae, a group of the Angiosperms often regarded as 
primitive, is of importance in regard to the evolution of the 
angiospermous vessel as compared with the origin of the vessel in 
Gnetales. THompson (5) concludes that the mode of origin of 
vessels in the two groups is quite different. Moreover, he states 
