Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
4. Polypodiaceae, the Polypody Family
6. Thelypteris Schmidel
1. Thelypteris palustris Schott -- Marsh fern
Rhizomes spreading and branching, slender, with a few appressed scales.
Fronds annual, only slightly dimorphic, mostly erect, the blades
pinnate-pinnatifid, lanceolate or oblong-lanceolate, 15-30(40) cm long, 8-15(20)
cm wide, puberulent on the rachis and midveins, acuminate, only slightly narrowed
at the base; pinnae usually 10-25 pairs, spreading, mostly alternate,
8-15(20) mm wide; petioles scaleless. Sterile fronds thin, delicate,
pinnules broadly oval, obtuse, 3-5 mm wide, veins once-dichotomous; petioles
shorter to longer than the blade. Fertile fronds surpassing the sterile
ones, more firm than the sterile fronds, the petiole longer than the blade;
pinnules oblong, 2-4 mm wide, the margins revolute; veins simple or once-dichotomous;
sori round, usually confluent on the back of the pinnules; indusium
attached at its center in the middle of the sorus, irregular in shape, usually
ciliate. Jun--Sep. Boggy or marshy places, where water is fresh; scattered from
ND to NE, especially common in the Sand Hills; (Nearly cosmopolitan; in N.Amer.,
Newf. to Man., s to GA and OK).
North American plants are var. pubescens (Lawson) Fern.
Previous Species -- Onoclea sensibilis L.
Return to Family -- Polypodiaceae -
The Polypody Family