VASCULAR ANATOMY OF ANGIOPTERIS EVECTA 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 290 
Huco L. BLomQuistT 
(WITH PLATES V—-VIII AND EIGHT FIGURES) 
In the study of the vascular anatomy of plants it has been real- 
ized that it is necessary to study the successive stages which the plant 
passes through in the progress of its development. Since it is the 
aim, first of all, to determine the position, interrelationship, and. 
structure of the different vascular components of the mature plant, 
this procedure not only facilitates the work, but in most cases 
perhaps is absolutely necessary. Likewise, in the search for facts 
which are to show indications of phylogenetic relationship, it is 
unnecessary to point out that it is in the developmental stages 
that these are most likely to be found. This method has proved 
to be especially necessary in the case of the Marattiaceae, for the 
vascular structures in the mature plant are not only very complex 
and difficult to interpret, but as the plant develops there are marked 
changes appearing in the anatomical structures from stage to stage. 
In some of the previous investigations on the anatomy of the 
Marattiaceae the failure to follow this method has led to much 
confusion and incorrect interpretation of the facts. 
Historical 
Considerable attention has been given to the Marattiaceae in 
the last fifty years, due chiefly to the evidence from geological 
records that this group of ferns, or a closely related group, was of 
great abundance and wide distribution in the past, and to the 
unique morphological and anatomical features which this group 
presents. Most of the work done on the anatomy of the Marat- 
tiaceae has been rather scattered and incomplete. ‘The reason 
for this has chiefly been the lack of material, as these ferns are 
restricted to rather inaccessible parts of the world. Although 
plants have been transported to many conservatories, this has not 
181] [Botanical Gazette, vol. 73 
