Fronds pinnate, one to five feet high. Pinnæ cut into oblong, obtuse lobes.
Fertile fronds taller than the sterile, having from one to five pairs of
intermediate pinnæ contracted and bearing sporangia.

[Illustration: Interrupted Fern. _Osmunda Claytoniàna_]

The fronds have a bluish-green tint; they mature their spores about the
last of May. The sterile fronds may be distinguished from those of the
cinnamon fern by not having retained, like those, a tuft of wool at the
base of each pinna. Besides, in Clayton's fern the fronds are broader,
blunter and thinner in texture, and the segments more rounded; the fronds
are also more inclined to curve outwards. They turn yellow in the fall, at
times "flooding the woods with golden light," but soon smitten by the early
frosts they wither and disappear. The interrupted fern is rather common in
damp, rocky woods and pastures; Newfoundland to Minnesota, south to North
Carolina and Missouri. Although fond of moisture it is easily cultivated
and its graceful outlines make it worthy of a prominent place in the
fern garden. Var. _dubia_ has the pinnules of the sterile frond widely
separated, and the upper-middle ones much elongated. Southern Vermont.

[Illustration: Interrupted Fern with the Fertile Pinnules Spread Open]

(3) CINNAMON FERN. BRAKES

_Osmunda cinnamomea_

Fronds one to six feet long, pinnate. Pinnæ lanceolate, pinnatifid with
oblong, obtuse divisions. Fertile pinnæ on separate fronds, which are
contracted and covered with brown sporangia.