Roth’s fern. 
219 
tion which I have not hitherto seen noticed; the main stem 
of the frond, instead of being regularly circinate, or composed of 
diminishing rings, like those of an Ionic volute, is doubled near 
the insertion of the second pair of pinnae, and turns back, form- 
ing a kind of loop. I have endeavoured to exemplify this in the 
accompanying figures, which are of the natural size. a shows 
the crown of the rhizoma before the fronds have begun to grow; 
h is the basal portion of the stem of a young frond, c, its apex; 
d shows the peculiar bend of the frond above described, and e 
the stem of the same frond in the same position, but stripped of 
its pinnae and scales. In favorable situations the fronds of 
mature plants, including the stem, measure five feet in length : 
this magnitude is, I believe, unequalled by any of our British 
ferns, except the common Brakes and Osmunda regalis. I se- 
lect for description a specimen for which I am indebted to Mr. 
John Ray of Epping, and first give its dimensions. Total length 
from the rhizoma to the apex of frond, sixty inches : from rhi- 
zoma to the insertion of the first pair of pinnae, twenty-four 
inches : from the insertion of the first pair of pinnae to the apex 
of frond, thirty-six inches. It must, however, be borne in mind 
that the relative length of the stem and frond is subject to great 
variation, being influenced by situation, degree of moisture, nature 
of soil, quantity of shade, and a number of other casualties. 
The length of the first pair of pinnae, seven and three quarter 
inches ; second pair, eight and a half inches ; third, eight and 
three quarters; fourth, nine inches; sixth, eight and three quar- 
ters ; seventh, eight ; eighth, seven ; ninth, six ; tenth, four and 
three quarters ; eleventh, four ; twelfth, three ; thirteenth, two 
and a half ; fourteenth, two : the remainder rapidly decrease in 
length, until the frond terminates in an acute point. The lengths 
of stem between the pairs of pinnae are these in the first in- 
stance four and a half inches ; in the second, three and a half; 
in the third, three and a quarter ; in the fourth, three ; in the 
fifth, two and a half ; in the sixth, two and a quarter ; in the 
seventh, two; in the eighth, one and three quarters ; in the ninth, 
one and a half ; in the tenth, one and a quarter ; in the eleventh, 
one ; in the twelfth, three quarters ; in the thirteenth, half an 
inch. From these admeasurements it will appear that the figure 
