Vascular Plants of North Carolina
Account for Southern Grapefern - Sceptridium biternatum   (Savigny) Lyon
Members of Ophioglossaceae:
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Section 2 » Family Ophioglossaceae
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Author(Savigny) Lyon
DistributionEssentially statewide, but scarce in much of the central and eastern Coastal Plain and scarce or absent in the Sandhills proper. Owing to confusion of this species with S. dissectum, collections seem to be under-represented in herbaria.

This is a Southeastern species, ranging north only to southern NJ and southeastern MO, and south to southern FL and eastern TX.
AbundanceCommon in most parts of the Mountains and Piedmont; infrequent to fairly common in the northern and western Coastal Plain, but seemingly quite uncommon elsewhere. We suggest a State Rank of S5 instead of the NCNHP's rank of S4.
HabitatThis is a species of acidic woods and thickets, often in mesic pine-hardwood forests. It also grows in bottomlands, other mesic to rich forests, and in some brushy habitats. Habitat distinctions between this species and the similar S. dissectum are not overly different or not well-described.
PhenologyFruits in late summer and fall -- August to October.
IdentificationThis species and S. dissectum are quite similar and are often confused -- not only in the field but as herbarium specimens as well, owing in part to the form obliquum of S. dissectum looking quite similar to S. biternatum. Each species is widespread in the state, and each has a height of about 1 foot with leathery sterile blades. In each the blade is triangular and about 5-6 inches long and wide, with the blade having a long petiole/stalk that joins the stipe very near the ground surface. S. biternatum has the fertile blade only bipinnately cut, whereas the other species has the fertile blade mostly tripinnate (or more). In S. biternatum, the "ultimate blade segments mostly oblong to obliquely lanceolate, the margins nearly parallel, the base cuneate, the apex relatively blunt" (Weakley 2018). In S. dissectum, the "ultimate blade segments trowel-shaped, the margins usually not parallel, the base truncate or obtuse, the apex relatively pointed". Thus, visually, S. biternatum blades have the many fewer pinnules nearly parallel-sided (oblong) and with a rounded tip; S. dissectum has typically more heavily-cut leaves, but even if not, the pinnules are strongly triangular and have somewhat pointed tips. Both have the fertile blade quite small and held high above the sterile blade, on a stalk often 8 inches tall or more.
Taxonomic CommentsThis species was formerly named as Botrychium biternatum. A few old references had this species lumped in with the old B. dissectum, named as B. dissectum var. tenuifolium.

Other Common Name(s)Sparse-lobe Grapefern
State RankS4 [S5]
Global RankG5
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