Danaea and other Marattiaceae . 
545 
between the outgoing leaf-trace meristeles and those of the 
dictyostele. Miss Shove, however, was not able to demon- 
strate the endodermis in relation to the 4 stem steles ’ (dictyo- 
meristeles) of the well-grown plant which she examined. 
The arrangement of the strands in the stem, except in the 
case of Danaea simplicifolia seedlings, was not gone into. 
From the earlier, and especially more recent, work in this 
line it is now possible to form a good idea of the general 
arrangement of the vascular system of these plants. Farmer 
and Hill’s models of the arrangements in Angiopteris and 
Marattia seedlings 1 mark an epoch in this study and are 
exceedingly helpful. To sum up then, these plants have a 
more or less complex adelosiphonic dictyostele, which is 
developed from a haplostele by the formation of leaf-gaps 
and a considerable tendency of the meristeles to branch and 
anastomose. 
No further information was gleaned with regard to the 
apical cell by the work done on Danaea simplicifolia seed- 
lings. Farmer and Hill (loc. cit., PL XVI, Figs. 14 and 15) 
seem to have got satisfactory evidence that in the seedlings 
of Angiopteris there is a single apical cell, and the writer 
came to the same conclusion with regard to the embryo of 
Danaea simplicifolia. But there is still room for further work 
in this direction. Farmer himself 2 and Bower 3 have both 
supported the oligocellular view. This is one of those 
questions to which it is very difficult to get a definite answer, 
perhaps because there is none, on account of the structures 
being still in a state of flux, so to speak. 
The Root. 
There is little variation in the root-structure throughout 
the group. Miss Shove, in her recent paper, has figured the 
1 Loc. cit., Plates XVI and XVII. 
2 J. B. Farmer, On the Embryogeny of Angiopteris evecta, Ann. of Bot., vi, 
p. 267. 
3 Bower, Comparative examination of the meristems of Ferns, Ann. Bot. iii, 
pp. 324, 325. 
