contains the mucilage which has rendered a variety of this species, 
common in New Zealand, to be employed as an article of food, as 
related in the Introductory Notice to this volume; and till better 
food was introduced, the consumption of Fern-root was there very 
great. The peasantry in England employ the stems of the Brake 
or Bracken for another purpose, by procuring an alkali from the 
burnt ashes, which they mix with water and form into balls. 
These latter are made hot in the fire, and then used to make lye 
for scouring linen ( Withering). 
The involucre of this Fern does in general, but not always, 
constitute a double membrane, first detected by Mr. Thomas 
Smith (see note in Sp. Eil. v. 2. p. 195), hardly of sufficient im¬ 
portance or constancy to constitute a generic distinction. 
In regard to geographical distribution, our herbarium is inun¬ 
dated with samples from all parts of the world, in all latitudes, 
from Lapland in 67° north, to Akaroa, in the south of New 
Zealand, and in tropical as well as temperate and subarctic 
regions. It is true the plant has gone under different names, 
according as it has been found in different and remote countries. 
A more than sufficiently full list of stations and synonyms has 
been given by us in the ‘ Species Eilicum,’ l.c. 
Plate 38. Portion of a caudex and stipes and young frond of Pteris aquilina, 
Linn .,—natural size. Pig. 1. Fertile segment,— magnified. 2. Portion of the 
involucre ,—more magnified. 3. Portion with the involucre laid open, showing 
its double nature and the capsular receptacle ,—more magnified. 
