Rugulose Grapefern

Sceptridium rugulosum is a fern in the family Ophioglossaceae.

Sceptridium rugulosum resembles S. dissectum (dissected grapefern) and S. multifidum (leathery grapefern), with which it commonly grows; however, its leaf emerges from the ground in late May, before the former and after the latter. The sterile deltoid-shaped leaf blade averages 4-8 cm (1.6-3.1 in.) long, with the petiole more or less the same length (shorter in sun forms and longer in shade forms). Unlike the rounded lobes of the leaf of S. multifidum, the leaf of S. rugulosum has angular lobes, mostly 2-5 mm (0.08- 0.20 in.) wide, with the edges coarsely and irregularly toothed. The marginal teeth are dentate (wide-based, squarish and outward-pointing), as opposed to the serrate (narrow, sharp, forward pointing and saw-like) teeth of S. dissectum forma obliquum. The leaf of S. rugulosum may maintain its green color, while the leaf of S. dissectum can turn a drab reddish color and then turn bronze-colored in autumn.