456 Browne . — Anatomy of the Cone and Stem of Equisetum . 
Literature cited. 
Barratt, K. : A Contribution to our Knowledge of the Vascular System of the Genus Equisetum. 
Annals of Botany, vol. xxxiv, 1920. 
Browne, I. : ( 1 ) Contributions to our Knowledge of the Anatomy of the Cone and Fertile Stem 
of Equisetum. Ibid., vol. xxvi, 1912. 
: ( 2 ) A Second Contribution to our Knowledge of the Anatomy of the Cone and 
Fertile Stem of Equisetum. Ibid., vol. xxix, 1915, 
. (3) a Third Contribution to our Knowledge of the Anatomy of the Cone and 
Fertile Stem of Equisetum. Ibid., vol. xxxiv, 1920. 
Chodat, R. : Les Pteropsides des temps paleozoiques. Archives des Sciences physiques et 
naturelles, vol. xxvi, pp. 1-44, 1908. 
Duval-Jouve, J. : Histoire naturelle des Equisetum de France. Paris, 1864. 
Janczewski, E. de : Recherches sur le developpement des bourgeons dans les Preles. Memoires 
de la Societe nationale des Sciences naturelles de Cherbourg, vol. xx, 1876. 
Milde, J. : Monographia Equisetorum. Nova Acta Academiae Caesareae Leopold. Caroli Ger- 
manici Naturae curiosorum, vol. xxiv, 1867. 
Pfitzer, E. : liber die Schutzscheide der deutschen Equisetaceen. Pringsheim’s Jahrbiicher fiir 
wissenschaftliche Botanik, vol. vi, 1867-8. 
EXPLANATION OF PLATE XXL 
Illustrating Lady Isabel Browne’s paper on the Anatomy of the Cone and Stem of Equisetum . 
Fig. 1. Transverse section of part of the axis of Cone B of E. sylvaticum a little above the 
insertion of the annulus. Note relatively numerous tracheides, some rather wide, x 65. 
Fig. 2. Transverse section of part of the axis of Cone b, taken a little below Fig. 1, but still 
slightly above the insertion of the annulus. Note the forking of some of the protoxylem canals ; 
other bundles still retain a single, relatively large carinal canal, such as characterizes all the bundles 
in the lower part of the internode, x 65. 
Fig. 3. Transverse section through part of the axis and annulus of Cone e of E. debile , showing 
a longitudinal view of one of the tracheides of a small free annular bundle. The photograph is 
taken at the level at which the annular vascular tissue approaches closest to the axial stele, x 250. 
Fig. 4. Transverse section of the stele of the cone of E. variegatum near the level of a node. 
As the sporangiophores are not inserted absolutely at the same level the section only passes through 
the insertion of two of the traces, x 125. 
Fig. 5. Transverse internodal section of the stele of E. variegatum. One of the bundles on the 
reader’s left shows the relatively large deeply seated tracheides of the metaxylem particularly clearly, 
x 125. 
Fig. 6 . Transverse section of the axis of E. debile between the last whorl of leaves and the 
insertion of the annulus. - Note that the bundles are situated opposite the grooves of the stem, x 30. 
Fig. 7. Transverse section of part of the stele of an internode of the cone of E . debile. Note the 
difference in the size of the bundles and the different degree of destruction of the protoxylem. Other 
points to be noted are the definite sheaths surrounding the bundles, the wide parenchymatous 
meshes, and the relatively large size of some of the deeper seated metaxylem tracheides. x 65. 
Fig. 8. Transverse section through a node of the stele of E. variegattun. This specimen was 
exceptionally large and the xylem unusually well developed, x 125. 
Fig. 9. Upper surface of the annulus of Cone B of E . debile , showing two stomata, x 506. 
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