128 BRITISH FERNS.— SUB-ORDER II. TRIBE 10. 
THE MARSH FERN. 
Nephrodium thelypteris. — Desvaux. 
(Lastrea thelypteris. — Bory.) 
An interesting fern, the associate of Osmunda regalis in boggy 
situations. It is readily cultivated, but prefers wet peat, as water 
is its especial requisite. The fronds vary from 6 inches to 4 feet, 
including the stem ; for at least half the frond is the naked stem. 
It is erect, and the fronds are of a delicate pale-green. Deciduous ; 
rhizoma creeping. Quite distinct from all other species. Widely 
spread, but very local. It is found in Devon, Somerset, Hamp- 
shire, the Isle of Wight, Sussex, Kent, Surrey, Berkshire, Essex, 
Norfolk, Suffolk, Cambridge, Bedford, Huntingdon, Warwick, 
Stafford, Hereford, Salop, Nottingham, Yorkshire, Cheshire, 
Westmoreland, Cumberland, and Northumberland. In Wales — 
Glamorgan, Pembroke, Carnarvon, and Anglesea. In Scotland — 
Forfar ; Shetland. In Ireland — Antrim, Galway, Mayo, Wicklow, 
and Kerry. 
Occurs throughout Europe; in North America; and North 
Africa. 
There are no varieties. 
THE MOUNTAIN BUCKLER FERN. 
N EPHRODIUM MONTANUM. — Baker. 
( Lastr e a montan a. — Moore . ) 
Fig. 38. — Nephrodium montanum. Pinna (showing fructification). 
Known as the “Sweet Mountain Fern,” owing to the strong yet 
pleasant scent of the fronds. Although recognised as a mountain 
fern, it is nevertheless found from the sea-level to an altitude of 
