Dennstaeditaceae

(Bracken family)

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GENERA (17) are divided into three tribes. The Tribe Dennstaediteae includes Dennstaedtia, Pteridium, Paesia, Microlepia, Saccoloma, Hypolepis, Blotiella, Lonchitis, Histiopteris, Leptolepia, and Oenotrichia. The Tribe Lindsaeeae includes Odontosoria, Lindsaea, Ormoloma, Tapeinidium, and Xyropteris. The Tribe Monachosorae is composed of Monachosorum.

THE DENNSTAEDITACEAE often bear epipetiolar buds which develop into branches. The family is also characterized by long-creeping stems with large, decompound leaves.

SORI are marginal, submarginal, or (rarely) abaxial. They are indusiate, and protected by an inrolled leaf margin as well as an extrorsely oriented flap of submarginal tissue on the ventral leaf surface.

SPORANGIA are thin-walled. The annulus is vertical to slightly oblique, well-developed, and interrupted by the stalk.

SPORES are mostly trilete, but occasionally monolete. They are homosporous, and borne in groups of 32 or 64. The spores lack chlorophyll.

STEMS range from erect and (rarely) arborescent, to short- or long-creeping. They may be small, stout or slender. Usually indurated, or (in Lonchitis) succulent, stems bear trichomes and/or scales.

PETIOLES lack stipules. They are characterized by a single, gutter-shaped vascular bundle, or several bundles that unite distally to form such a bundle.

LEAVES may be hairy or glabrous, but lack scales. Ranging from 20 cm to 7 m in length, they are usually pinnate and are circinate in bud.

THE VASCULAR CYLINDER may be protostelic with internal phloem, siphonostelic, or (rarely) dictyostelic.

RHIZOMES may be hairy or glabrous.

THE GAMETOPHYTE is epigeal, and photosynthetic. Obcordate to reniform, it is slightly thickened centrally. Archegonia are borne on the lower surface, usually centrally. Antheridia are also borne on the lower surface, but mostly apart from the archegonia.

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