GROUP IV
FERTILE AND STERILE FRONDS LEAF-LIKE AND SIMILAR; SPORANGIA ON OR BENEATH A REFLEXED PORTION OF THE MARGIN
20. BRAKE. BRACKEN. EAGLE FERN
Pteris aquilina
Almost throughout North America, in dry, somewhat open places. One to two feet high ordinarily, occasionally much higher.
Fronds.—Solitary, one to two feet wide, cut into three primary divisions which are twice-pinnate, widely spreading at the summit of an erect, stout stalk; sporangia borne in a continuous line along the lower margin of the frond; indusium formed by the reflexed edge of the frond.
Of all ferns the Brake is the most widely distributed. It occurs in one form or another in all parts of the world. With us it grows commonly from one to two feet high, occasionally higher. In Oregon it attains a height of six or seven feet, in the Andes of fourteen feet.
It is a vigorous and often a beautiful and striking plant, growing abundantly on sunny hillsides and in open woods.
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