92 
NATURE STUDY. 
As regards the divisions and subdivisions of the leaves o^ 
ferns the nomenclature which expresses them is quite puzzling. 
It is no disgrace to find these terms meaningless at first. The 
only disgrace is in not caring to make the mental effort essen¬ 
tial to comprehending them. It is not half so hard as it seems 
to be to master a class of unfamiliar terms 
when they are so rationally and logically 
employed as they are in the scientific work of 
this closing year of the nineteenth century. 
One does not have to be a Latin scholar to 
know that “ bi ennial ” means “ two-yearly ” ; 
neither need he in order to know that “ bi- 
FIG. 4. 
pinnate ” means “ twice pinnate.” All the 
trouble comes in the beginning. The mastering of the first 
dozen jaw breakers gives confidence for all following struggles 
and the monsters soon vanish like morning mists. 
The leaves of the royal fern are said to be “ bi-pinnate ” 
(Fig. 5) because each pinna (branch) is divided into several 
“ pinnules ” (branchlets). Those of the 
other two species would be called “pin¬ 
nate ” (one-branched) were it not that the 
branches themselves are almost cut to the 
midrib, so an intermediate term has to be 
used expressing this approach to the twice- 
branched form. This term is “bi-pinna- 
tifid ” (Fig. 4). To go farther, some ferns 
have leaves that are thrice divided ; accord¬ 
ingly they are termed “ tri pinnate ” ; and a form between this 
and bi-pinnate is called “ tri-pinnatifid,” meaning almost thrice- 
branched. 
Our three species of Osmunda fortunately require only two 
of these awkward terms. The royal fern has bi-pinnate leaves 
only , the cinnamon fern has the fertile leaves bi-pinnate and 
the sterile ones bipinnatifid ; Clayton’s fern has only bi pinna- 
tifid leaves. 
fig. 5. 
