Cor mack. — On Equisetum. 
EXPLANATION OF FIGURES IN PLATE VI, 
Illustrating Mr. Cormack’s paper on a Cambial Development in Equisetum. 
Reference letters. 
bb , branch-bundle. 
cc, carinal canal. 
d, the ‘ denser layer.’ 
end., endodermis. 
g, g' , side groups of xylem. 
I, leaf. 
lb, leaf-bundle. 
phi., phloem. 
r, protoxylem. 
t, tannin. 
vc, vallecular canal. 
xy, xylem. 
x , seen in a different focal 
plane. 
Fig. i. Diagram from a radial section through a node and portions of two inter- 
nodes of E. maximum. The plane of section passes through the middle of the 
carinal canal and vascular bundle of the lower internode. The darkest shading 
represents the wood. In the ground-tissue, darkness of shading represents relative 
shortness of the parenchymatous cells. ( x io.) 
Fig. 2. Diagram from a transverse section through the node of E. maximum , 
cutting two bifurcating bundles at slightly different relative levels. ( x io.) 
Fig. 3 . From a transverse section through a mature node of E. maximum, 
showing radial rows of cells intercalated between mature tissues of the bundle. 
(x 1 75 -) 
Fig. 4. Two radial rows, similar to those of Fig. 3, more highly magnified, 
(x 294.) 
Fig. 5. From a transverse section through a mature internode of E. maximum ; 
cc, carinal canal ; r, remains of protoxylem ; g, g', side-groups of xylem differen- 
tiated during the elongation of the internode. ( x 175.) 
Fig. 6. From a transverse section through a node of a bud of E. maximum, 
showing fewer cells than Fig. 3 does ; the intercalation of rows of cells (cambial 
activity) is just beginning. ( x 175.) 
Fig. 7. From a transverse section through the internode adjacent to the node 
from which Fig. 6 was drawn. This figure shows that, in the internode of a bud, 
the bundle attains about as many elements in radial thickness as does the mature 
internode (Fig. 5) ; whereas the adjacent node (Fig. 6) has not yet as many ele- 
ments as the mature node (Fig. 3) ; thus there must be cambial activity. ( x 175.) 
Fig. 8. From a tangential section of a node of E. maximum, showing cambium- 
like cells in tangential view. ( x 175.) 
Fig. 9. From a radial section through a node of E. maximum, showing radial 
view of the cambium-like cells. ( x 1 75-) 
Fig. 10. From a transverse section of the internode of a young calamite showing 
a ‘ carinal canal ’ occupied by the remains of protoxylem ; rings marked x lie in 
a lower focal plane. ( x 294.) 
Fig. 11. From same section of calamite-internode as Fig. 10, showing fascicular 
and inter-fascicular cambium and secondary tissue derived from it. ( x 294.) 
