Anatomy and Cone of the Fertile Stem of Equisetum. 701 
4. The non-alternation of some of the strands of the cone at the node 
is due to poor development of xylem in this region causing the persistence 
of the meshes on either side of a strand. 
5. The anatomy of the axis supports the view that the sporangiophores 
are whole appendages and not lobes of a sporophyll or leaf. 
6. The branching of some of the vascular bundles in the neighbour- 
hood of the insertion of the annulus affords an indication of nodal character 
at this level. This is confirmed by the anatomy of an abnormal specimen of 
E. ar reuse. 
7 . In the upper part of the fertile stem of E. limosum a diaphragm of 
the usual t) pe was not found; instead there was an inverted hollow cone 
of dark brown cells, hanging freely down for a little distance in the central 
cavity and continuous upwards, above the breaking up of the nodal xylem 
with the locally somewhat thickened and dark brown endodermis. 
My thanks are due to Professor Oliver, F.R.S., in whose laboratory at 
University College, London, this work was carried out ; and to Mr. T. G. 
Hill for much advice and assistance. 
Literature quoted. 
Bower, F. O. (1) : Studies in the Morphology of the Spore-producing Members. I : Equisetineae 
and Lycopodineae. Philosophical Transactions of the Royal Society, Series B, vol. clxxxvi, 
1893. 
(2) : The Origin of a Land Flora. 1908. 
Browne, I : The Phylogeny and Inter-relationships of the Pteridophyta. New Phytologist Reprint, 
1909. 
Buchtien, C. : Entwicklungsgeschichte des Prothalliums von Equisetum . Bibliotheca Botanica, 
Heft No. 8, 1887. 
Campbell, D. H. (1) : Messes and Ferns. 1895. Second edition, 1908. 
(2) : The Affinities of the Genus Equisetum. The American Naturalist, 1905. 
Chauveaud, G. : Recherches sur le developpement de l’appareil conducteur dans la racine des 
Equisetac^es. Bulletin de la Soci^te Philomathique de Paris, 9 e serie, vol. iv, no. 1, 1902, 
p. 26. 
Cormack, B. J. : On a Cambial Developement in Equisetum. Annals of Botany, 1893. 
Duval Jouve : Histoire Naturelle des Equisetum de France. Paris, 1864. 
Eames, A. J. : On the Occurrence of Centripetal Xylem in Equisetum. Annals of Botany, 1909. 
Famitzin, A. : fiber die Sprossbildung bei Equiseten. Bulletin de l’Academie des Sciences de 
Saint-Petersbourg, 1876. 
Fritel, P. H., and Viguier, R. : Les Eqtiisetum fossiles et leur structure. Revue Generale de 
Botanique, tome xxi, 1909, pp. 129-42. 
Goebel, K. : Uber die Fruchtsprosse der Equiseten. Berichte der deutschen botanischen Gesell- 
schaft, Bd. iv, 1886. 
Gwynne-Vaughan, D. T. : Remarks upon the Nature of the Stele of Equisetum. Annals of 
Botany, 1901. 
