This is the common species of northern New England and the Canadian Provinces. The fronds differ very widely in form and a great many varieties have been pointed out, but the fern student, having first learned to identify the species, will gradually master the few leading varieties as he meets them.
Those growing in warm, sunny places where the fruit-dots when mature incline to cover the whole back of the frond are called "sun forms." These are varieties TÝPICUM and ELÀTIUS, both with the pinnæ obliquely ascending (including variety angustum of D.C. Eaton), but the latter has broader fronds with the pinnules of the sterile fronds oblong-lanceolate, somewhat acute and strongly toothed or pinnatifid.
[Illustration: Varieties of Lady Fern Left to right--lst and 2nd, Var. typicum; 3d, elatius; 4th, rubellum; 5th, uncertain, perhaps confertum]
Var. RUBÉLLUM has the sori distinct even when mature; its pinnules stand at a wide angle from the rachis of the pinna and are strongly toothed or pinnatifid with obtuse teeth. This variety favors regions with cool summers, or dense shade in warmer regions. The term RUBÉLLUM alludes to the reddish stems so often seen but this sign alone may not determine the variety. It occurs throughout the range of the species, being a common New England fern. Fernald remarks that this is also a common form of the species in southern Nova Scotia.
Among other varieties named by Butters are CONFÉRTUM, having the pinnules irregularly lobed and toothed; joined by a membranous wing, the lobes of the pinnules broad and overlapping, giving the fern a compact appearance; LACINIÀTUM with pinnules very irregular in size and shape, with many long, acute teeth, which project in various directions. "An abnormal form which looks as if it had been nibbled when young."
These varieties are represented in the Gray Herbarium.
(2) THE LOWLAND LADY FERN
ATHÝRIUM ASPLENIÒIDES
Rootstocks creeping, not densely covered with the persistent bases of the fronds. Stipes about as long as the blade. Scales of the stipe very few, seldom persistent, rarely over 3-16 of an inch long. Fronds narrowly deltoid, lanceolate, widest near the base, the second pair of pinnæ commonly longest. Indusia ciliate, the cilia (hairs) ending in glands. Spores dark, netted or wrinkled.