Anatomico-physiological Relations in the Spermophyte Shoot. 159 
resumes activity, and gives rise to a new apical cell which divides to produce 
the axillary bud. Thus, in the envelopment of the internode with a leaf- 
skin through the extension below the node level of the lowermost cells 
of the leaf primordium, the scheme of leaf development in E guise turn 
is wholly comparable with that described above for a Spermophyte. In 
both, these extensions cover and are fused with the internode below the 
node at which the leaf separates from the axis, and keep pace with the 
elongation of the enclosed core. Equisetum is the type which Hofmeister 
Fig. 34. Longitudinal section through the stem apex of Equisetum telmateia (reproduced 
from Sachs’s ‘ Lehrbuch’, ist ed., p. 336). x,y indicate the highest, youngest rudiment of an annular 
swelling which will develop into a leaf-sheath ; b, b, the same older ; bs, apical cells of a still older 
leaf-rudiment ; g, rows of cells from which the vascular bundles are derived ; i, the lowest layers 
of cells of the segments ; 1 r, the rudiment of the cortex of the intemode ; s, apical cell of stem. 
takes in illustration of that Berindung of the stem which, he considered, 
probably occurs in all leaf-bearing plants from Char a upwards. He was, 
however, unable to furnish evidence in support either of this general pro- 
nouncement or of the more definite statement that the stem is represented by 
the pith alone and that all the tissue external to it is to be regarded as foliar 
in character, and based his view on phylogenetic considerations and grounds 
of general probability . 2 
1 It is of interest to note in the present connexion that in the legend accompanying this figure 
in both the first and second editions it is stated of the cells indicated by the letter ‘ V that they take 
no part in the formation of the leaves, but that in the legend to the same figure in De Bary’s 
Vergleichende Anatomie this sentence does not appear. 
2 See Flora, 1863, p. 173. 
