Taxon	Illustrator ⠉
	Pteridium aquilinum var. latiusculum Pteridium aquilinum var. pseudocaudatum Pteridium aquilinum var. caudatum	John Myers John Myers John Myers

Plants terrestrial, often forming colonies or thickets. Stems subterranean, slender, long-creeping; hairs pale to dark, jointed; scales absent; true vessels present (absent in other Dennstaedtiaceae genera in the flora). Leaves widely spaced, broadly deltate, 0.5–4.5 m. Petiole glabrous to short-hairy, without prickles, with stem buds near base, vascular-bundles numerous, U or O-shaped in cross-section. Blade 2–4-pinnate, rachis and costae grooved adaxially; rachis without prickles; nectaries at base of proximal and sometimes distal pinnae. Segments pinnately divided, ultimate segments ovate to oblong to linear, base extending proximally on costae (decurrent) or proximally (surcurrent), margins entire. Veins free or joined at margin by commissural vein beneath sori, pinnately 2–3-forked. Sori ± continuous, covered by recurved, outer false indusium and obscure, extrorse, inner true indusium. Spores tetrahedral-globose, trilete, very finely granulate. x = 26.

Distribution

Almost worldwide

Discussion

Species 1 (1 species, 4 varieties in the flora).

Selected References

Page, C. N. 1976. The taxonomy and phytogeography of bracken---A review. J. Linn. Soc., Bot. 73: 1--34.

Perring, F. H. and B. G. Gardener, eds. 1976. The biology of bracken. [Symposium.] J. Linn. Soc., Bot. 73(1--3): i--vi, 1--302.

Tryon, R. M. 1941. A revision of the genus Pteridium. Rhodora 43: 1--31, 37--67.

Lower Taxa

Pteridium aquilinum