182 BOTANICAL GAZETTE [MARCH 
appreciably altered the situation, because of the tardiness in the 
germination of spores and the slowness of growth of the 
gametophyte. 
The investigations on the anatomy of the Marattiaceae up to 
1900 have been reviewed by Miss SHOVE (12). It is evident that 
the work up to that time was rather unsatisfactory, as only mature 
stems were dealt with, and the material in most cases was limited 
to one specimen. Miss SHOVE also worked with a mature stem. 
Since then, however, several invest gations have been carried out 
in which the younger stages have been studied. In 1902 FARMER 
and Hitt (8) published the results of an investigation on the 
development of the vascular anatomy in Angiopteris evecta, which 
was supplemented by a paper on the younger stages by CAMPBELL 
(2) in 1909. A thorough investigation on the development of the - 
vascular anatomy of Maraitia alata was carried out by Miss 
CHARLES (7) in 1911. This was the first investigation on the anat- 
omy of this group based on an abundance of material. In 1917 
West (13) added another contribution to the knowledge of the 
vascular anatomy of this group in a paper on the anatomical 
structures of Danaea spp. and several of the other genera. This 
investigation also was based on an abundance of material. 
In comparing the conclusions drawn in this literature, it is 
evident that the vascular anatomy of the plants of the six genera 
of the Marattiaceae is very complex, but shows a striking simi- 
larity in facts both in the developmental stages and the more 
mature plants. Differences which are reported are mainly in 
details and in the interpretation of facts. There seems to be an 
agreement of opinion that the sporophyte of the Marattiaceae is 
traversed by a central strand of vascular tissue, called a dictyostele, 
from which roots and leaf traces arise. This stele is at first solid, 
or protostelic, then passes to a more or less tubular form, a soleno- 
stele, which is soon broken open by leaf gaps which are at first 
wholly repaired, but later overlap, so that the central strand 
becomes a banded structure which appears crescent-shaped in 
cross-section. This at first is simple, but later becomes complicated 
by the appearance of commissural and medullary strands. Dis- 
agreement is shown in regard to the meristematic regions, the 
