410 BOTANICAL GAZETTE [DECEMBER 
quently an apparent absence of foliar gaps, but that in all the 
species which he studied in serial sections a gap was really present, 
although in a single section it might appear to be absent. More- 
over, it was shown by this author that in the case of the horseshoe- 
shaped stele of the leaf in species of Osmunda and Todea, the passing 
off of the pinnular traces always left clear gaps in its wall. More- 
over, both Mr. Sinnott and Professor FAULL’ have made it quite 
clear that the hypothesis of GwyNNE-VAUGHAN as to the primi- 
tive absence of foliar gaps in the Osmundaceae receives no support 
whatever from a consideration of the anatomy of the seedling of 
living species. Consequently, we may say of the hypothesis 
advocated by GWYNNE-VAUGHAN that it is not definitely con- 
firmed by the fossil evidence, and that all the evidence derived 
from the consideration of the anatomy of the stem, leaf, and 
seedling of living species is entirely against his view. It may 
consequently be stated with confidence that at the present time 
there is no valid proof in favor of the original absencé of foliar 
gaps in the Osmundaceae. 
The English school of anatomists has been well advised in 
making its stand upon the stelar origin of the pith as opposed to 
its derivation by the inclusion of extrastelar fundamental tissue 
within the central cylinder, for if that view is once overthrown, 
a number of other conceptions commonly held in England fall 
with it to the ground. If it be clear that the pith is originally an 
inclusion of the fundamental tissues within the central cylinder, 
certain interesting conclusions immediately follow. One of the 
most important and far-reaching generalizations of modern plant 
anatomy, and one which receives the fullest support from the con- 
siderations of all the main groups of vascular plants, is that the 
foliar strand perpetuates the original condition of the wall of the 
stelar tube. There is distinct evidence in the case of the Osmunda- 
ceae, Ophioglossaceae, Lyginodendreae, Equisetales, etc., that the 
central cylinder of the stem was once composed of concentric 
fibrovascular bundles, since bundles of this type persist in the 
leaf trace or sporophyll trace of these various groups. This 
inevitably follows if it is admitted, as apparently it must be from 
7 FAuLL, J. H., The stele of Osmunda viniomcieets Trans. Canad. Inst. 8:515- 
534- 909. | 
