Mnioloma novaezelandiae J.J.Engel
Mnioloma novaezelandiae J.J.Engel, Cryptogamie 27: 111. f. 1; 2: 1–3. 2006.
Holotype: New Zealand, South Is., Southland Land District, Fiordland Natl. Park, Charles Sound, south side of Gold Arm, 340 m, 8 April 2002, Renner CMS J156 T/10 (F); isotype: (CHR).
Plants rather flexuous, procumbent, distinctly brownish, the stems more deeply so, the shoots medium in size, to 1.6 mm wide. Branching frequent, irregular, uniformly ventral-intercalary, at times 2 per underleaf axil, the branches uniformly leafy in some populations, one population with branches leafy as well as stoloniform, geotropic and whip-like. Stems conspicuously striolate in surface view, in cross section with cortex in 10–16 rows, in an ill-defined layer of slightly thickened, markedly brown-pigmented cells; medullary cells with walls thin, pigmented or not. Rhizoids hyaline or pale brown, at immediate base of underleaves, few per underleaf base or sporadic, the rhizoid surface finely but distinctly roughened, the apices at times dendritic. Leaves virtually flat, widely spreading, contiguous to weakly imbricate, the insertion not extending to stem midline dorsally, delimiting a leaf-free strip of 2 cells wide, the stem widely exposed in dorsal view; leaves ovate-oblong to rounded-quadrate, on mature shoots 480–600 µm wide × 600–730 µm long; apices broadly rounded to truncate, often unevenly repand, sporadically retuse; margins often unevenly repand, especially the dorsal, otherwise entire, the free tangential wall of marginal cells straight or somewhat bulging, the margin not crenulate and not with marginal cells widest at the radial walls and with the intervening free wall arched toward the cell lumen; leaves with apex and margins with 1(2) rows of marginal cells mostly subisodiametric, smaller than intramarginal cells and forming an incipient border, the marginal cells with free wall straight to bulging to, at times, angularly projecting (particularly toward the distal end of the free wall), making the margin locally minutely denticulate, the marginal cells sporadically somewhat radially elongated (to 2.2:1), especially toward the leaf bases, but these cells on the whole narrower than intramarginal cells and contributing to the aspect of a border of differentiated cells. Cells of median sector of leaf thin-walled, trigones absent or minute, the cells 25–36 µm wide × 34–49 µm long; surface conspicuously papillose, the surface becoming striate toward basal cells. Oil-bodies occupying conspicuous portion of volume of lumen, smokey grey, 6–11(13) per cell in median portion of leaf, narrowly elliptic to fusiform, less often broadly elliptic, some globose, finely botryoidal, 4.8–6.2 × 10.6–16.3 µm, broadly elliptic ones 5.8 × 8.2 µm, the globose ones 5.8–6.2 µm in diam. Underleaves inserted on 4–5 rows of stem cells, 1.7–2.6× stem width, distant, slightly convex (ventral view), oblate to reniform, the apices equally or unequally bilobed to retuse, the lobe apex often rounded, each with a slime papilla, the 2 papillae often closely juxtaposed, the cells ringing the sinus not much differentiated from those below or if elongated, then not much narrower; the sinus often notch-like; margins entire, the free tangential wall of marginal cells straight or somewhat bulging, locally and sporadically imperceptibly crenulate via marginal cells widest at the radial walls and with the intervening free wall arched toward the cell lumen. Asexual reproduction lacking.
Dioecious. Androecia unknown. Gynoecia on very short ventral-intercalary branches, bud-like when unfertilized. Marsupium fleshy, cylindrical, brownish, similar in pigmentation to stem, rhizoidous, the summit with a few, vestigial bractlets.
Sporophyte unknown.
Distribution and Ecology : Endemic to New Zealand: South Island (120–340 m), North Island (ca. 800–840 m). Known from Fiordland, Westland and Auckland EPs.
Known only from a few sites, one in the southwestern sector of South Island (type), in Westland (Mt. Te Kinga) and Coromandel Peninsula (Mt. Moehau). On Mt. Moehau plants occurred on soil admixed with Psiloclada clandestina and Bazzania tayloriana deep in a protected pocket of a vertical bank at ca. 800–840 m in an area of rocky outcrops and shrub-heath communities including Dracophyllum recurvum, Lepidothamnus laxifolius, Coprosma foetidissima, Oreobolus pectinatus and Corokia buddleioides. The type occurred at 340 m on a soil bank in a forest dominated by Nothofagus menziesii, N. solandri var. cliffortioides growing with Zoopsis argentea, Bazzania adnexa and Tylimanthus tenellus (see Renner, 2003). The Mt. Te Kinga specimen occurred on a wet soil bank under Blechnum colensoi and B. novae-zelandiae, in Dacrydium cupressinum and Weinmannia racemosa forest. It was growing with Leptopteris superba, Microlaena avenacea, Metrosideros diffusa, Nertera dichondrifolia and the bryophytes Cryptopodium bartramioides, Distichophyllum kraussei, Lepidozia spinosissima, Leucobryum candidum, Psiloclada clandestina and Zoopsis setulosa.
Comments : Mnioloma was first reported for New Zealand by Renner (2003), who used the name Mnioloma fuscum, a broadly distributed species. Engel (2006c) recognized the New Zealand population as a distinct species and differentiated it from M. fuscum on the basis of leaf and underleaf characters, the presence of a dorsal leaf-free “gutter,” as well as differences in ventral merophyte number. In the field the species has the appearance and habitat of the moss genus Distichophyllum. On closer examination, it resembles a Bazzania in color, size and the shape of the underleaves, but the leaf apices are repand or entire rather than 3-fid.
