474 Boodle.—Anatomy of the Hymenophyllaceae. 
protoxylems (represented by dots) still distinct; in Fig. 31 
the { stele,’ produced by the union of leaf-trace and stele of 
axillary branch, is fusing with the stele of the stem, the two 
phloems having become continuous ; and in Fig. 32 the fusion 
is complete, and internodal structure is attained. In passing 
down the internode the xylem becomes more rounded, but 
the protoxylems of the stem and leaf-trace remain distinct, 
very nearly as far as the next node below, so that a transverse 
section of an internode usually shows two protoxylems in the 
stele. In one case the protoxylems were still separate at 
a distance of 11 mm. below a node, but at 18 mm. below, 
which was a few mm. above the succeeding node, the proto¬ 
xylems were practically fused. Thus it is seen that the 
protoxylem-groups in the stem of this species of Trichomanes , 
as in Hymenophyllum , are the direct continuations of those 
of the leaf-traces. The two protoxylems seen in the internode 
are connected with the next and next-but-one leaves above. 
The attachment of the stele of the axillary branch to the 
leaf-trace also agrees with what is found in Hymenophyllum. 
A comparison of the leaf-trace in Fig. 29 with the petiolar 
bundle in Fig. 27 shows that after leaving the cortex of the 
stem its phloem becomes again continuous in the base of 
the petiole, to be interrupted once more in the upper region 
of the petiole. The roots are rather stout, and their steles 
may be attached by a broad base to the xylem on the lower 
side of the stele. 
T. Prieurii , Kunze. 
This plant differs from all the cases described above, but 
agrees with some other species of its genus, in that the stem 
is upright, and the leaf-arrangement is radial. The phylotaxis 
is two-fifths. The stem has a solid-looking mass of xylem 
consisting of tracheides mixed with parenchyma in about the 
same proportion as T. radioans, or with less parenchyma. 
The protoxylems are internal, and as many as three may 
sometimes be seen in a transverse section. A fair-sized group 
of sclerenchyma-fibres accompanies the leaf-trace into the stele, 
