Boodle . — Anatomy of the Schizaeaceae. 389 
series with another, the structure of the transitional region was 
ascertained. By soaking one of the seedlings for nearly twenty- 
four hours in Eau de Javelle before embedding, a series was 
obtained, which was satisfactory through the greater part of 
its length. Figs. 31-31 (excluding Fig. 33) are sections of the 
axis in ascending order. Fig. 31 shows the structure of the 
primary root. It is of the typical diarch type, but is not quite 
mature. One point, however, in which the majority of Ferns 
would perhaps show a difference, is that here the first-formed 
phloem-elements (ppk.) are adjacent to the protoxylems, so 
that there are four protophloems. The same mode of 
development is also found in the lateral roots of the young 
plant. The root stele bends in towards the prothallus in 
the region of the foot, and becomes vertical again, just as 
in Lygodium. It may then or soon afterwards be called 
the stem-stele, as it has lost the characteristic root-structure, 
and its xylem consists of a solid mass of tracheides of fairly 
uniform size. The first leaf-trace is then given off (Fig. 33), 
and the xylem of this leaf-trace (pc' l) consists of only about 
six tracheides. One or two small ones which were crushed 
are not shown in the drawing. Fig. 33 is the xylem of the 
same leaf-trace on its way out through the cortex. Soon 
after the separation of the first leaf-trace, a parenchyma-cell 
appears inside the xylem (Fig. 34). It may be connected by 
one or more obliquely placed cells with the conjunctive 
parenchyma surrounding the xylem at a lower level, and not 
with the leaf-trace; e.g. the parenchyma-cell seen in Fig. 34 
had a downward connexion of this kind on the side away from 
the leaf-trace. The second leaf-trace is given off leaving the 
stele much as in Fig. 34. Then two or three more soft-walled 
elements appear adjoining the first parenchyma-cell in the 
xylem, and of these one or two are probably sieve-tubes. 
These immersed elements change their position slightly, so 
that the xylem becomes open, and one of them comes into 
contact with the external conjunctive parenchyma. A stage 
of this kind is shown in Fig. 35, where the two elements 
embedded deepest in the xylem are probably sieve-tubes, 
