Polypodiaceae

(Polypody family)

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GENERA (ca. 40) are divided into several tribes, and include Polypodium, Microgramma,Loxogramme,Grammitis, and Pleurosoriopsis.

THE POLYPODIACEAE are an isolated family, but may be distantly related to the Gleicheniaceae. Nearly all family members are epiphytes.

SORI are round to elongate, and borne in row(s) on each side of the costa. They lack an indusium.

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

SPORES are homosporous, and occur in groups of 32 or 64. They may lack chlorophyll. Mostly trilete, spores may be monolete.

STEMS range from erect to long-creeping. They may be small to massive, or slender to filiform. Indurated or hardly sclerotic, stems bear scales.

PETIOLES lack stipules, and eventually absciseto leave a short projection on the rhizome.

LEAVES are entire, pinnatifid, or variously forked or pinnate. They may be glabrous, or have short hairs or scales. Circinate in bud, they range from 3 cm to 2 m in length.

VENATION is free, or in part reticulate. The vascular cylinder may be solenostelic of dictyostelic.

RHIZOMES are scaly.

THE GAMETOPHYTE is epigeal, and photosynthetic. Obcordate, spathulate or ligulate, it is more or less thickened centrally. The gametophyte may be glabrous, or bear trichomes. Archegonia are borne on the lower surface, centrally or near the sinus. Antheridia are borne on the upper or lower surfaces, apart from the archegonia.

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