Allisoniella nigra (Rodway) R.M.Schust.
Allisoniella nigra fo. subobtusa R.M.Schust., Nova Hedwigia 22: 143. pl. 5: 1–11. 1972 (1971).
Holotype: New Zealand, Stewart Is., Pegasus Creek, Schuster 49581a (herb. Schuster).
Leaves at least locally 2-stratose toward their bases, broadly quadrate when flattened, a little broader than long (490–520 µm wide × 390–440 µm long), bilobed to 0.4–0.55, sporadically to 0.6; lobes to 27–32 cells broad at base, variable, tending to be concave and/or sulcate abaxially, as long or a little longer than broad, usually blunt to narrowly rounded (sporadically acute to subacute); sinus obtuse to, infrequently, rectangular, often gibbous. Cells weakly thick-walled to almost guttulate with rounded lumina. Otherwise unknown.
Distribution and Ecology : New Zealand: Stewart Island. Known only from the type, which grew in a shallow stream over boulders subject to inundation.
Comments : Plants are intermediate between subsp. nigra and typical subsp. novaezelandiae. It is similar to or approaches fo. novaezelandiae in the mostly broadly obtuse to narrowly rounded leaf lobes, but the leaves are bilobed as deeply as in subsp. nigra.
