DENNSTAEDTIACEAE

BRACKEN FAMILY

Alan R. Smith and Thomas Lemieux

Plant in soil; rhizome hairy, less often scaly, sometimes from bud near petiole base
Leaves alike; petiole strongly grooved on upper side, glabrous or hairy, rarely scaly, in X -section vascular strands 1–many in U shape; blade generally 1–5- or more pinnate; axes, blades glabrous or hairy, rarely scaly; veins pinnate from midrib, generally forked beyond, free except sometimes at margin of fertile segments
Sporangia at or near margin, generally ± covered by reflexed segment margins (false indusia); true indusium 0, or linear, purse-shaped, opening toward margin or fused with it to form cup; stalk cells in 1–3 rows; spores spheric or elliptic, scar of 3 radiating branches or linear
Genera in family: ± 17 genera, ± 375 species: especially tropical. Variously defined; Pteridium sometimes in its own family.

PTERIDIUM

BRACKEN, BRAKE

Rhizome generally deep, long-creeping, branched; scales 0
Leaf: petiole near base blackish, with dense brownish hairs, above straw-colored, ± glabrous; blade 2–4-pinnate, lower surface generally hairy; 1° leaflets sometimes with nectaries in axils; veins free except at margin of fertile segments
Sporangia marginal, generally continuous except at sinuses; tips, on connecting veins, ± covered by false indusium (sterile segment margins similarly modified); true indusium inconspicuous or 0; spores spheric
Species in genus: ± 5 species: temp, tropical
Etymology: (Greek: small Pteris , fern)
Reference: [Tryon 1941 Contr Gray Herb 134:1–31, 37–67]
Often considered (e.g., by Tryon) a single, ± worldwide, highly variable sp., but especially in tropical, subtropical, species seem distinct.

Native

P. aquilinum (L.) Kuhn var. pubescens Underw.

Leaf arched; petiole 10–100 cm; blade generally 15–150 cm, widely-triangular, leathery, generally 3-pinnate below, lower 1° leaflets generally longest, ± 45° away from axis; segments or lobes generally 0.5–2 cm, 3–6 mm wide, oblong, round at tip, hairs on lower surface generally dense, straight or ± kinked, clear, sometimes on upper
Ecology: Pastures, woods, meadows, hillsides, partial to full sun
Elevation: 0–3200 m.
Bioregional distribution: California Floristic Province (except Great Central Valley)
Distribution outside California: to Alaska, South Dakota, nw Mexico; also eastern Canada, ne US
Other vars. in eastern US, Mex, Eurasia, Africa, Pacific. TOXIC in quantity to livestock and humans; cooking removes some toxins, but carcinogens may remain
Horticultural information: 4, 5, 6, 15, 16, 17, IRR: 1, 2, 3, 18, 24 &SHD: 7, 8, 9, 10, 14, 19, 20, 21, 22, 23; INV also STBL.