5 1 8 Brebner . — On the Anatomy of 
For the purposes of this investigation, material, more or 
less complete, was available of species of Danaea , Angiopteris , 
Marattia and Kaulfnssia , for which the writer is greatly 
indebted to Sir William Thiselton-Dyer, Director of the 
Royal Botanic Gardens, Kew, Professor F. O. Bower, Glasgow 
University, Professor F. W. Oliver, University College, Lon- 
don, and the late Mr. George S. Jenman, British Guiana. 
The writer likewise had the privilege of cutting a section of 
the petiole of a herbarium specimen of the new genus 
Archangiopteris , discovered by Henry in 1899 1 . 
The subject will be dealt with in the following order: — 
(1) Development of the vascular system of Danaea 
simplicifolia , Rudge. 
(2) Comparative anatomy of the frond, stem and root of 
the Marattiaceae. 
The importance of the Marattiaceae as a group and the 
desirability of studying it both from the developmental, 
anatomical and palaeontological aspects has been so well set 
forth in the important recent contributions just referred to, 
that further dwelling on this point is unnecessary. It is hoped 
that the present paper will help to fill up another gap or two 
in our knowledge of this interesting section of the Pteridophyta, 
although from the nature of all such investigations there can 
be no finality. 
It will be well, however, before beginning the descriptive 
part of this paper, to say a few words about the stelar 
terminology to be used. The exceedingly valuable advance 
made by Van Tieghem in emphasizing the importance of 
the vascular conducting cylinder as a whole by his stelar 
terminology has been recognized by the general adoption of his 
terms. Also, owing to the influence of the fresh position thus 
assumed, a great step forward has been taken in the study 
and comprehension of the vascular system of plants. This 
study, in its turn, has led to the recognition of the fact, that 
a certain number of the terms did not fit the resulting new 
views. Further, fresh terms have been devised to express 
1 Christ u. Giesenhagen, Flora, 1899. 
