F I L I C E S 
BRITANNIC^. 
75 
light, the diafragms, in the internal fmall tubes, may be eafily dif« 
cerned. 
The outer leaves are greatly fwollen and dilated at the bafe, as at a, 
b, c ; where the fru(ftification is lodged. The ftile and ftigma are placed 
in the hollow part of the bafe of the outer leaves; the germin is fup- 
ported by a cordate valve, or flower-cup, as at e ; and the edges of the 
inflated bafe, of thefe outer or female leaves, is a thin fine membrane, 
which fo clofely embraces and furrounds the gibous part of the male leaf 
within as to exclude the water. 
The inner or male leaf, b, opens on the outer or gibous fide of the 
bafe, within the embraces of the female leaf- Its fructification confifts 
of a roundifh anthera, without filament ; and it refts on a cordate valve 
or flower-cup, fimilar to that of the female. By the above admirable 
contrivance, the two flowers come in near contaCt with each othe'i^ and, 
though in the bottom of deep lakes, are fecured from the intrufion of the 
water. 
The feed-veflel is of an oblong form, confifling of two valves, filled 
with white globular feeds; each of which is girt round with a prominent 
ring, as at d. After the difcharge of the feeds, the outer leaves fall off 
and perifh, and the next in order perform the fame office a fucceeding 
year; and the number of leaves is kept up by a fupply of young ones 
from the centre. 
Grows in lakes on high mountains. I have dragged it out of feveral 
lakes on Snowden^ and it has been fent me from Wefttnorelands 
0. 
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