Sinnott.—Foliar Gaps in the Osmundaceae. 11 7 
6. The Osmundaceae are therefore very properly placed in Jeffrey’s 
phylum Pteropsida, the members of which are primitively phyllosiphonic. 
I am under obligations to Mr. A. J. Eames and to Professor Jeffrey for 
their kindness in supplying material, and wish to express to the latter my 
sincere thanks for advice during the course of the work. 
This investigation was carried on in the Phanerogamic Laboratories of 
Harvard University. 
Bibliography. 
1. Jeffrey, E. C. : The morphology of the central cylinder in the Angiosperms. Canadian Inst. 
Trans., vi, 1900. 
2 . -: Are there foliar gaps in the Lycopsidia? Botanical Gazette, xlvi, 1908, 
pp. 241-58. 
3 . Kidston, R., and Gwynne-Vaughan, D. T.: On the Fossil Osmundaceae, Part I. Trans. 
Royal Soc. of Edinburgh, xlv, Part 3, 1907. 
4. Zenetti, P.: Das Leitungssystem im Stamm von Osmunda regalis und dessen Uebergang in 
den Blattstiel. Bot. Zeit., liii, 1895, p. 53. 
5 . Seward, A. C., and Ford, S. O.: The Anatomy of Todea. Trans. Linn. Soc. Bot., ser. 2, vi, 
London, 1903. 
6. Tansley, A. G.: Lectures on the evolution of the filicinean vascular system. New Phytologist, 
Reprint No. 2. 
7 . Penhallow, D. P. : Osmundites Skidegatensis , n. sp. Trans. Roy. Soc. of Canada, ser. 2, viii, 
sec. 4, 1902. 
8. Leclerc du Sablon : Recherches sur la formation de la tige dans les Fougeres. Ann. Sc. Nat., 
7® sdr., xi. 
9 . Faull, J. H.: The Anatomy of the Osmundaceae. Botanical Gazette, xxxii, 1901, pp, 381-419. 
10. Chandler, S. E.: On the arrangement of the vascular strands in the ‘ seedlings ’ of certain 
leptosporangiate ferns. Annals of Botany, xix, No. 75, 1905. 
11. Eames, A. J.: On the occurrence of centripetal xylem in Equisetum. Annals of Botany, xxiii, 
No. 92, 1909. 
DESCRIPTION OF PLATES XI AND XII. 
Illustrating Mr. Sinnott’s paper on Leaf-gaps in Osmundaceae. 
Fig. 1. Osmunda cinnamomea. Leaf-trace leaving the cylinder, apparently without making 
a complete gap. x 40. 
Fig. 2. 0 . cinnamomea. The same trace as in Fig. 1 a little higher up in the stem, showing 
the well-marked gap subtended by it. x 40. 
Fig- 3- O. regalis. Leaf-t.race departing from the cylinder in an apparently gapless fashion, x 40. 
Fig. 4. O. regalis. The narrow gap eventually subtended by the trace shown in Fig. 3. x 200, 
Fig. 5. Todea superba. Leaf-trace departing without making a complete gap. x6o. 
Fig. 6. T. superba. The same trace as in Fig. 5, showing the well-marked gap which finally 
appears, x 40. 
