West. — A Contribution to the Study of the Marattiaceae . 365 
development of the vascular system in the young sporophyte of Danaea 
simplicifolia , Rudge. 
Jeffrey ( 36 ) very briefly described the arrangement of the vascular 
tissues in young stems of Danaea , in which he observed a tubular central 
cylinder interrupted by foliar gaps, and a single medullary strand which 
fused with the wall of the stelar tube above the foliar gaps. According 
to this investigator, the medullary strand later develops into a tube or 
a series of strands ; finally, the stelar system is further complicated by the 
appearance of another series of strands. This arrangement of the vascular 
strands was compared with that which obtains in Matonia . 
In his monograph on the Psaronieae and Marattiaceae, Rudolph ( 51 ) 
described the course of the vascular strands in a small piece of an old stem 
of an unidentified species of Danaea from Brazil. This stem showed 
a radial organization, but unfortunately the lower portion was missing. 
A series of outline drawings of transverse sections of this stem, in which 
the individual bundles were numbered ( 1 . c., Taf. Ill, Figs. 5-14, 16), 
illustrated the description ; such a method, however, is most unsatisfactory 
because the extreme complexity of the structures concerned leads to 
confusion in the mind of the reader. 
Campbell (20) has recently published a critical study of the develop- 
ment and arrangement of the stelar tissues in three species of Danaea 
(D. jamaicensis, D. Jemnani , and D. elliptica ). This botanist puts forward 
the view that the stele of the very young sporeling consists of a sympodium 
of leaf-traces which below merge insensibly into the diarch primary root, 
and suggests that in these young sporelings there is no stem in the strict 
sense. Only a passing reference is made to the vascular anatomy of the 
adult plant, which, apart from an increase in the number of leaf-traces 
and commissural strands, is assumed to be essentially similar to that of the 
young plant (1. c., p. 175). 
Thus, it is evident that no satisfactory account of the stelar anatomy 
of the adult sporophyte of Danaea has yet been published. Since this is 
the only genus of Marattiaceae at present known which includes both 
radial and dorsiventral species, it seemed that a comparative study of the 
development and arrangement of the stelar tissues in Danaea alata and 
Dajiaea nodosa respectively might yield both useful and interesting results. 
With this end in view, three wax models (Text-figs. 3 and 4, A ; PI. XXI, 
Fig. 1 A), showing clearly the transition from the simple stelar system of 
the young sporeling to the highly complex arrangement of vascular strands 
in the adult plant, were built up. 1 These models, although constructed 
from three plants, form what is practically a continuous scheme of the 
stelar system in the rhizome of Danaea alata , Sm., and for this reason the 
following description of the vascular anatomy of the genus Danaea is mainly 
1 Unfortunately the actual specimens from which these models were built up were not sketched 
before being cut up ; however, PI. XXI, Fig. 2, and PI. XXII, Fig. 9 B, respectively represent plants 
of about the same age as those from which the two larger models were made. 
CCS 
