Allisoniella nigra (Rodway) R.M.Schust.
Allisoniella nigra subsp. nigra var. acutiloba J.J.Engel, Novon 17: 313. 2007.
Holotype: New Zealand, Stewart Is., Bald Cone, 80 m, Glenny 9317 (F); isotypes: (AK, CHR 574634, HO).
[Fig. 128: 2, oil-bodies, p. 558]
Plants stiff and rigid, dark yellowish brown (but pale toward the shoot apices) to fuscous. Leaves widely spreading to squarrose, the lobes decurved gently, giving the overall aspect of a slightly adaxially convex leaf, the leaves bifid to 0.35–0.5; lobes 17–24 cells wide at the base, with margins slightly recurved, the lobes plane or weakly and inconspicuously abaxially sulcate, subacute to acute, terminating in a single cell or a uniseriate row of 2 ± isodiametric cells. Cells of the lamina and lower sectors of the lobes arranged in vertical rows; surface delicately and inconspicuously striate-papillose. Oil-bodies occupying moderate portion of cell volume, hyaline, 2–3 per median lamina cell, globose to broadly elliptic, finely papillose, the spherules slightly protruding beyond membrane. Chloroplasts large for cell and oil-body size.
Plants autoecious.
Distribution and Ecology : New Zealand: Stewart Island (30–80 m).
Occurring at ca. 30 m on bedrock submerged in water above Belltopper Falls (Port Pegasus, Stewart Island). On Bald Cone (Pegasus Harbor, Stewart Island, 80 m) it was found on granite bedrock in a small streambed, partially inundated, the streambed surrounded by Leptospermum scoparium – Empodisma minus scrub 50 cm high. Accompanying species were Rhacocarpus purpurascens, Blindia robusta, Cheilolejeunea albovirens and Riccardia sp.
Comments : With the addition of var. acutiloba, the subsp. nigra is added to the New Zealand flora. The variety appears to match the type of Allisoniella nigra of Tasmania except for sexuality. Clearly further study on the complex is necessary, particularly to establish presence of the dioecious condition for some populations of A. nigra.
