88 
THE AMERICAN BOTANIST. 
from a sheathing base but without aligule where the two 
join. Like the grasses, the sedges spread by underground 
runners but the former tend to form mat-Hke growths 
while the latter incline to tufts and tussocks. The sedges 
are also remarkable for usually having the internode bear- 
ing the flower many times longer than the others. 
From the lact that very careful work is necessary to 
identif)^ the various species of grasses and sedges, the 
group is one to attract discriminating botanists and has 
always been a favorite with close students. The identifi- 
cation of the species is a most excellent drill in observation 
and accuracy and is likely to prove interesting even to the 
beginner who will attempt it. 
THE ROUND-LEAVED MAIDEN HAIR. 
Adiantum reniforme. 
There is probably no genus in the world more distinct- 
ly marked than Adiantum^ to which the maiden-hair ferns 
belong. The peculiar one-sided pinnules with the main 
rib running along the lower margins, and the oblong sori 
concealed under overlapping lobes of the opposite margins 
are so characteristic that the merest novice has no trouble 
to refer all ordinary forms to their proper places. More 
difficulty would be experienced, however, if all the ferns of 
the world were examined, for then it would be seen that 
all maiden-hair ferns do not have pinnules of the one-sided 
type and we should have to fall back on the characters of 
the sorus and indusium to be sure of our plants. The 
species that we have chosen for illustration is one of the 
latter kind. From a casual glance at its fronds we would 
scarcely take it for a fern at all, much less a maiden-hair 
fern, but the characteristic form of the fruit dots settles 
the question beyond doubt. It may be added, however, 
that maiden-hair ferns with simple entire fronds are ex- 
ceedingly rare, there being only one other species with this 
peculiarity in the world. Both are natives of the Old 
World, Adiantum reniforme being found in Madeira and 
Teneriffe, and A. Parisbii growing in the Malay Peninsula. 
