192 
ASPIDIACE^. 
Lastr^ea rigida, Presl, Babington. 
Aspidium rigidum, Hooker. 
This beautiful and very distinct species was added to our 
British Flora in 1815, by the Rev. W. T. Bree. It seems en- 
tirely confined to limestone rocks in mountainous districts, and 
has hitherto, as far as regards Great Britain, only been found in 
three English counties. 
Lancashire. — It was found by the Rev. J. Smythes, near 
the top lock of the Lancaster and Kendal canal.^ 
Westmoreland. — Mr. Simpson informs me he found it ^Gn 
great profusion growing out of broken limestone, on the declivity 
of a hill just by the border of Lancashire : ” he observes, “ I 
never saw any fern in such masses, several hundred fronds being 
together in a compact bundle, so much so indeed that when 
I had pulled two hundred no diminution of the quantity was 
observable.” Miss Beever, in a letter of a subsequent date, 
says it grows ‘‘ most profusely on and near Arnside Knot.” Mr. 
Finder, at a still later period, writes thus : I met with Lastrcea 
rigida in great profusion along the whole of the great scar 
limestone district, at intervals between Arnside Knot, where it 
is comparatively scarce, and Ingleborough, being most abundant 
on Hutton Roof crags and Farlton Knot, where it grows in the 
deep fissures of the natural platform, and occasionally high in 
the cleft of the rocks ; it is generally much shattered by the 
winds, or cropped by the sheep, which seem to be fond of it. 
With regard to the shape of the frond, I may mention that 
among some hundreds of specimens I found but one or two 
which agreed with your figure [see the right hand figure, p. 191] 
drawn from an Ingleborough specimen, all mine being more or 
less triangular [see the left hand figure], and not having the 
lower pair of pinnae shorter than those in the upper and middle 
part of the frond : the fronds of young plants are remarkably 
triangular. The two forms of frond no doubt depend upon the 
situation, whether sheltered or otherwise, and on other causes. 
Phytologist, 478. 
