Notes,. 
779 
The structure of the * stele/ as seen in transverse section, is singularly 
uniform in essential histological details throughout the group. It may 
be said to be of the Fern type, but there is no endodermis (i.e. in the 
case of well-grown plants), and the pericycle is not characteristically 
present. 
The protoxylem is usually endarch— at any rate in the frond — but 
it may be mesarch. 
The protophloem is internal. This was first demonstrated in the 
steles of the stem by Miss Shove \ It has since been found to be 
internal in the steles of the frond of two species of Danaea and of 
Marattia alata. There can be little doubt that the internal position 
of the protophloem is general for the steles of both stem and frond in 
this group of Ferns. 
3. Apical growth. 
All the fresh evidence obtained while studying the seedlings of 
Danaea simplicifolia is in favour of an initial group, consisting of 
a few cells, both in stem and root. 
4. Roots. 
Nothing new has been observed in the roots of the Marattiaceae. 
In the roots of Danaea simplicifolia there is what might be called 
a fibrous pith, which is early differentiated, even before the main mass 
of the xylem has begun to be lignified. 
GEORGE BREBMER. 
University College, Bristol. 
THE ANATOMY AND DEVELOPMENT OP THE STEM 
IN THE PTERIDOPHYTA AND GYMNO SPERMS 2 .— Com- 
paratively little attention has been directed to the subject of the 
development of the stem. This research concerns itself chiefly with 
the development of the cauline fibro-vascular skeleton, since this 
appears to be most interesting from the phylogenetic and morpho- 
logical standpoints. A study of numerous examples drawn from the 
main groups of the Pteridophyta and Gymnosperms has led to the 
conclusion that the polystelic type of Van Tieghem does not originate, 
as he states, by the repeated bifurcation of the epicotyledonary central 
1 Annals of Botany, vol. xiv, 1900, p. 497. 
2 Abstract, republished from the Proceedings of the Royal Society, vol. Ixix, 
1901, 
