214 
D. T. Gwynne-V aughan. 
petioles. In fact the epidermis of the stem at the axil of each leaf has 
sunk deeply inwards so as to form a pit or pocket projecting into the 
ground tissue of the stem. These epidermal pockets, as they may 
he called, run downwards for about three or four millimetres, and 
at the same time penetrate so far inwards that they reach right into 
the central ground tissue within the lattice-work tube of vascular 
strands ; there they end blindly. The leaves are inserted so closely 
together that from three to six of these pockets may be cut across 
in one transverse section. Their size and form will vary from one 
section to another according to the distance of the section below 
the insertion of the leaves to which they respectively belong. In 
Fig. 41. Fig. 42. 
Figs. 41 and 42. Onoclea gcrmanica. Transverse section of the erect 
stock. In all the figures the epidermal pockets are left blank, 
the ground-tissue of the stem is dotted, the meristeles of the 
stem are shaded black and the leaf-traces are shaded with 
parallel lines. 
many sections a definite stem hardly appears to exist at all, but the 
axis of the plant is apparently made up of a number of petiolar 
bases inserted one upon another (fig. 41). All the vascular strands 
in the axis appear to lie in these leaf bases, but by tracing their 
course upwards through a series of sections it is seen that the 
larger of them (after giving off the small leaf-traces) pass inwards 
before the petiole is free from the stem, and then move over so as 
to take up the same position as before in a ridge that continues the 
base of a higher petiole. These strands (shaded black in the 
figures) are therefore strictly cauline and constitute the vascular 
lattice-work proper to the stem. 
I'he stolon of Onoclea germanica is much narrower than the 
erect stem. Its leaves are separated by long internodes and there 
