72 THE BRACKEN, 
The fronds are produced all summer, rising from the 
rootstock at intervals of from six inches to six feet. 
They are triangular in outline and ternately divided ; 
that is, the lowest pair of pinne are so much larger than 
the rest, that the frond appears as if made up of three 
nearly equal divisions. Counting these lowest divisions 
as pinne, the frond is three times pinnate below and 
passes by every gradation upward to the pinnate apex. 
In very large specimens the basal pinnules on the lower 
pinne are again lobed or parted, making this part of the 
frond nearly quadripinnate. The pinnules are narrow, 
two or three times longer than broad and set fairly close 
along the midrib. 
The fruit is borne in a continuous narrow line on the 
margin of the pinnules and is covered by an indusium 
formed of its reflexed edges. There is said to bea 
second indusium, also, attached within the receptacle and 
spreading beneath the sporangia but this is not to be 
discerned in most specimens. When young the outer 
indusium forms a silvery-white edging on the underside 
of the pinnules, but as the spore-cases mature, they peep 
from under it, and turning a deep rich brown, cause the 
frond to look as if embroidered. 
The bracken has many common names. Brake, 
bracken and eagle fern are the only ones in ordinary use 
in America. The last, as well as the specific name 
aquilina, is supposed to have been given to the plant 
from some eagle-like characteristic, but whether this is 
found in the claw-like crosiers, the broad fronds like an 
eagle’s wings, or the spread-eagle which some fancy they 
see in a section of the stem, is not apparent. Erne fern, 
an old name for this species, is merely another variation 
for eagle fern, erne or herne, signifying eagle. The name 
