SUB-SECTION LASTREA. 
T 33 
THE MALE FERN. 
Nephrodium Filix-mas —Richard. 
(Lastrea Filix-mas— /V*?. r/.) 
Fig. 39. — Pinna (showing fructification of Nephrodium Filix-mas). 
Under Presl’s Lastrea Filix-mas we have apparently three 
species. They are too distinct, both in their normal forms and in 
their varieties to enable us to consider them as mere sections, 
unless we look upon N. propinquum as the mountain form of 
N. paleaceum. As our object is, to produce a Handbook of all the 
distinct varieties, it has been thought best to follow Wollaston’s 
arrangement. 
According to Mr. G. B. Wollaston (who pointed out these dis- 
tinctions some years ago), we have the following characteristics : — 
Fronds and 
N. Filix-mas. 
N. PALEACEUM.* 
N. PROPINQUUM. 
pinnce 
convex 
plane 
. concave 
Colour . . 
shining pale green . 
shining deep green . 
. dull pale green 
Fronds . . 
partially deciduous 
evergreen or sub- 
evergreen 
quite deciduous 
Indusium . 
not embracing spore 
embracing spore 
embracing spore 
cases ; evanescent, 
cases ; persistent, 
cases ; persistent 
Texture of 
disrupted 
entire 
entire 
frond . . 
papery 
coriaceous 
. soft 
Pinnules . 
saw-toothed 
scarcely toothed . . 
. double saw-toothed. 
The concave character of the frond is not uncommon on moun- 
tains, or when plants grow under difficulties, such as insufficiency 
of soil, unfavourable climate, etc. This may be seen on Ben 
Lawers, with the examples of half-starved Polypodium vulgare, 
P. dryopteris, and P. phegopteris. Diminished size, wavy out- 
line, crisp, and a more or less abnormal and starved-look are 
features familiar to all mountain Botanists. This is also to be seen 
with regard to ferns growing on rocks and walls in the Lowlands. 
* Lastrea pseudo-mas, Wollaston. There can be no doubt this is the 
Aspidium paleaceum of older writers, hence its adoption. 
