(1) Oak Fern
Phegópteris Dryópteris. Thelýpteris Dryópteris
Fronds glabrous, broadly triangular, ternate, four to seven inches broad, the divisions widely spreading, each division pinnate at the base. Segments oblong, obtuse, entire or toothed. Fruit-dots near the margin. Rootstock slender and creeping from which fronds are produced all summer, in appearance like the small, ternate divisions of the bracken.
This dainty fern has fronds of a delicate yellow-green, “the greenest of all green things growing.” Its ternate character is shown even in the uncoiling of the fronds, the three round balls suggesting the sign of the pawnbroker. The parts of the oak fern develop with great regularity, each pinna, pinnule and lobe having another exactly opposite to it nearly always. In rocky woods, common northward; also in Virginia, Kansas and Colorado. A fine species for cultivation at the base of the artificial rockery.