4. Ophioglossum vulgatum L. (southern adder's tongue)
Pl. 10e,f; Map 50
Ophioglossum vulgatum var. pycnostichum Fernald
Stems short-cylindrical, sometimes slightly thickened. Leaves usually 1 per
stem, 5–30 cm long. Vegetative portion usually flat, not folded longitudinally,
sessile to short-stalked, ovate to lanceolate, the base truncate to rounded or
short-cuneate, the tip rounded, not sharply pointed. Veins all about the same
thickness, forming a simple network, the areoles not enclosing thinner networks
of veins. Fertile portion 1–4 times as long as the sterile portion. 2n=
960, about 1,320. April–August.
Eastern Missouri north to Lincoln County (eastern U.S.
west to Texas and disjunctly in Arizona, Mexico,
Europe, Asia). Rich soils of mesic forests,
often in the bottoms of ravines; also in bottomland forests.
The leaves of this species are shiny when fresh. In contrast to other Missouri species, O.
vulgatum is usually found in deep shade, rather than in sunny habitats.
Reports of the northern adder's tongue, O. pusillum Raf. (O. vulgatum
var. pseudopodum (Blake) Farw.), from Missouri were based upon misdetermined
specimens of O. vulgatum. The northern adder's tongue does not occur
south of central Iowa
in the Midwest.