Dryopteris Thelypteris, Gray (Aspidium Thelypteris, Swartz). Marsh Fern. Rootstock creeping: lvs. scattered, clear green, 1-2 ft. long; margins of the spore-bearing pinnae often strongly convolute: sori 10-12 to each segm. Canada to Fla. and Texas.—A form with pinnae variously forked at tip is known as Pufferae.