324 Bower . — The comparative examination of the 
in a median longitudinal section of this apex 1 , which I took 
to be the single initial cell, but I was not able to state whether 
it had two or three edges, or what is the succession of seg- 
ments cut off from it : further, the question was left open 
whether the presence of one initial is constant for the species, 
and the evidence was not considered as by any means conclu- 
sive. When in Ceylon, I took the opportunity of collecting 
apices of well-grown plants both of Marattia fraxinea , and of 
Angiopteris evecta , and though even this material has been too 
scanty for working out all the details of so complicated an 
apex as this has proved to be, still it has sufficed for acquiring 
some further knowledge of the meristems of this interesting 
family. 
In large plants the apex of the stem is found to be almost 
perfectly flat, distinctly more so than in Osmunda : the very 
slightly swelling apical cone is unusually wide, and since the 
cells composing it are of almost equal size throughout, a 
careful examination of the tissue as seen in surface view is 
necessary before the succession of the cell-divisions can be 
traced. Treatment with ‘ eau de Javelle ’ was found useful for 
distinguishing the older or principal walls from the younger 
cell-walls, and thus assisting in the recognition of groups of 
cells of common origin. If a transverse section including the 
external surface of the apical cone of Angiopteris be thus 
treated, a central point may be recognised where the principal 
walls meet, and this point is often characterised by a highly 
refractive thickening of the wall : this is the central point of 
genesis of the meristem (Fig. 27) : around this point are dis- 
posed cells which appear to be constant neither in number nor 
in form : it is true that the four cells marked (*) in Fig. 27 can 
be regarded as initial cells for the whole meristem, and it is 
possible to recognise how in this case the whole of the broad 
area of tissue represented might have been derived from them, 
the apical structure being thus coincident with that described 
by Schwendener for the root ; but it is to be observed .that 
this was the most favourable and distinct specimen of the 
1 Phil. Trans. 1884, Part II, Plate 37, Fig. 9. 
