398 Chandler.— On the Arrangement of the Vascular Strands 
before the first leaf-trace. The first two leaf-strands are quite simple, and 
the resulting gaps are merely bridged by the endodermis. At about the 
third leaf-trace a fundamental-tissue pocket appears in the central phloem 
in a way almost identical with that described above for other ferns. 
A patch of endodermal cells appears, quickly followed at a higher level by 
an endodermis surrounding a patch of ground-parenchyma cells con- 
taining tannin. The inner endodermis becomes continuous with the outer 
at the succeeding leaf-gap, and the subsequent elaborative changes of the 
vascular system are essentially the same as in the case of other ferns with 
similar fundamental-tissue pockets. 
The most striking character in the anatomy of this plant is the 
abnormal width of the pericycle. The excessive width results not only 
from the treble, and sometimes quadruple nature of the layer, but also from 
the large size of the cells themselves. The latter are densely crowded with 
starch, and are not arranged in radial rows. The ground-tissue in young 
plants, or in the lower parts of older ones, is in striking contrast with 
the thin-walled pericycle. It is wholly composed of cells with thick, 
brown, sclerotic walls, even the outer tangential walls of the endodermis 
being strongly sclerosed ; higher up the plant, however, a thin-walled band 
of ground-tissue separates the vascular strand from the outer sclerotic 
portion. It will be remembered that an exactly similar state of affairs 
occurs in Osmunda % and also in Lygodium , as described by Boodle. 
Todea Fraseri, H. and G. 
By the kindness of Mr. Boodle the writer had the opportunity of 
examining seedlings of two species of Todea , viz. T. hymenophylloides 
and T. Fraseri . Examination of the former fully confirmed the account 
of the transitional region given by Seward and Ford 1 , who found in this 
fern an essential agreement with the transitional changes occurring in 
Osmunda regalis (Leclerc du Sablon). 
The changes occurring in T. Fraseri closely resemble those of 
T. hymenophylloides. The root possesses a very simple vascular strand, 
the xylem being diarch and consisting of but a few tracheides. The sieve- 
tubes are somewhat ill-defined, as is also the endodermis. The ground-tissue 
is highly scelerotic. The usual change of the xylem plate to a solid strand 
occurs, and the first leaf-trace is formed while the xylem of the protostele 
is still very small in amount, consisting of about six or seven tracheides. 
No leaf-gap is formed, a few tracheides surrounded by phloem being merely 
nipped off from the stem strand. After the first trace, the xylem increases 
in quantity, and the sieve-tubes become much more prominent. The 
endodermis is very indistinct, and readily torn in the process of cutting ; in 
1 The anatomy of Todea. Trans. Linn. Soc., 2nd ser., vol. vi, 1903. 
