78 
P. 0. BOWER. 
dacete might also be a transitional type in respect of the 
structure of the meristem in the root. The result justified mv 
expectations, and the observations to be detailed below will 
afford material help towards the solution of the problem as to 
the mode of transition from growth with one apical cell to that 
with a group of two or more initial cells. 
Osmunda regalis. — Transverse sections. 
In describing the manner in which the arrangement of the 
primary meristem of the root of Osmunda regalis differs 
from that generally accepted as characteristic of the roots of 
Ferns , 1 the results obtained from transverse sections will be 
detailed first. As the irregularities are in some cases very 
great, and as there is not uniformity of structure in the meri- 
stem of different roots of this species, even when taken from 
the same plant, it is obvious that, in order to attain a clear 
idea of the irregularities, the study of transverse sections is 
more likely to lead to safe conclusions than that oflongitudinal 
sections. Anyone who has made preparations from the roots 
of those Ferns which have an almost diagrammatic regularity of 
arrangement of the meristem, will, I think, allow that the study 
of transverse sections of these is more easy and secure than 
that of longitudinal sections. But if there be no definite regu- 
larity of arrangement of the meristem the difficulties presented 
by the study of longitudinal sections are very greatly increased, 
since it is in this case so much less easy to determine whether 
any given section be accurately longitudinal, and almost im- 
possible to be sure whether it be accurately median. In ob- 
1 Naegeli and Leitgeb, ‘ Beitrage z. wiss. Bot.,” Leipzig, 1868. It may 
here be stated that I have made sections from the apices of roots of Cyathea 
insignio, Eat., Gleichenia circinatn, Sw., Gleichenia flabellata, 
R. Br., and Aneimia phyllitidis, Sw., and have found in all of these 
that the structure of the meristem corresponds in its chief points to that 
described by Naegeli and Cramer for the Polypodiaceae. It is clear that the 
prevalence of this type of meristem among the leptosporangiate Ferns makes 
the abnormality of structure in the Osmundaceae still more interesting than it 
would otherwise have been. 
