Metahygrobiella drucei R.M.Schust.
Metahygrobiella drucei R.M.Schust., J. Hattori Bot. Lab. 26: 273. 1963.
Holotype: New Zealand, North Is., Mt. Hector, West Peak, 4500 ft., Schuster 60444 (F).
Holotype: New Zealand, South Is., Fiordland, Key Summit, 15 Dec. 1962, MacMillan, Morice & Taylor (herb. Hodgson no. 12634) (MPN!); isotype: (CHR – absens).
Holotype: New Zealand, North Is., Tararua Mtns., N face of Mt. Hector, ca. 4300 ft., Zotov s.n. (CHR no. 7492!); isotype: (MPN, Hodgson herb. no. 477, non vidi).
[Figs. 126, 127; Fig. 128: 1, oil-bodies, p. 558]
Plants flaccid, very soft-textured and spongy, hyaline and whitish below, the distal parts of leaves, bracts and perianths reddish to purplish, intense purplish in sun forms, medium, to 1000 µm wide. Stems hyaline, with a rather well-defined hyaloderm, the medullary cells thin-walled. Rhizoids not seen. Branching common, the branches of the Frullania type, often several per shoot; ventral-intercalary commonly present, leafy or at times initially stoloniform but ultimately becoming leafy, the collar low, rather broad. Leaves contiguous to weakly imbricate, subtransversely oriented, the insertion transverse or subtransverse to weakly succubous in dorsal third, but with remainder of insertion distinctly succubous, the leaves concave, often deeply so, often appearing inflated and billowed out, orbicular-subquadrate to subrectangular, in situ flaring dorsally and partially overlapping dorsal sector of opposing leaf, 500–870 µm wide × 700–1100 µm long, symmetrically bilobed to (0.25)0.3–0.5; lobes often sharply incurved, subequal, medium acute, terminating in a single cell or a uniseriate row of at most 2 cells, the tip cell at most slightly longer than wide, the lobes 9–16 cells wide at base, the lobe margins entire. Cells in median sector of lamina with walls very thin, completely devoid of trigones, 19–29 µm wide × 28–43 µm long to 24–36 µm wide × 50–60(80) µm long, the cells of lobes in regular tiers. Oil-bodies lacking or with numerous, hyaline, minute (ca. 1 µm in diam.) oil-droplets. Underleaves absent but at times locally present and then of a few cells (e.g., biseriate at base + single cell capped by a slime papilla), at times distinct, wider than the stem and ovate to elliptic, undivided and entire. Asexual reproduction lacking. Fungal partner an ascomycete.
Dioecious. Androecia terminal but eventually becoming intercalary on elongated, leafy axes, subfoliose; bracts similar to leaves except somewhat more closely imbricate, with bases more concave and the lobes erect; antheridia 1 per bract, the stalk 2-seriate; bracteoles lacking. Gynoecia terminal on long or leading leafy axes; bracts and bracteoles in 3 series, the bracteoles of first series subquadrate and with a retuse apex, those of second series large, obovate, with apex retuse to irregularly bilobed; bracts much larger than the leaves, free dorsally, rather sharply and irregularly longitudinally undulate, 3-lobed, the lobes blunt to narrowly rounded at the summit, the lobe and lamina margins entire; bracteoles similar in size to bracts, free or distinctly connate on one side and free on the other, the apices bilobed, the lobes similar to those of the bracts. Perianth rather long, elliptic to subfusciform, cylindrical below, trigonous above (often distinctly so), with 2 keels lateral + 1 ventral, narrowed to the contracted mouth; mouth crenulate but with some sectors entire and straight, without suggestion of protruding free ends of cells; perianth 1–2-stratose toward base.
Seta of the 8 rows of outer cells and 4(5) rows of inner, somewhat smaller cells. Capsule short-ellipsoidal, the wall 2(very locally 3)-stratose, 35–36 µm thick; outer layer of cells tiered, subrectangular, but becoming quadrate with occasional secondary transverse cell wall divisions, with two-phase ontogeny obscure: all or most longitudinal walls with continuous sheets of secondary, pigmented wall material and frequent nodules, lending the walls a sinuous appearance, the alternating longitudinal walls at times with thickenings less well developed (but rarely altogether absent) and then with a suggestion of two-phase development; inner layer of cells with semiannular bands well developed, usually complete, the bands rather closely spaced, narrow, sporadically forked, particularly at the cell ends.
Spores 13–15.4 µm in diam., with low but distinct, close papillae and short-vermiculate markings; spore:elater diam. ratio 1.4–1.8:1. Elaters rather rigid, at most only moderately tortuous, 8.6–9.6 µm wide, tapering to ends, bispiral to the tips, the spirals 2.9–3.4 µm wide, closely wound.
Distribution and Ecology : Endemic to New Zealand: South Island ([825]920–1500 m).
A helophyte, occurring in penalpine and alpine areas over peaty soil in saturated or near-saturated conditions associated with pools, tarns and ponds, often associated with Sphagnum. On the summit plateau of Mt. Maungatua (30 km W of Dunedin) occurring over saturated peaty soil at pool margins in an area of tussock grassland with mosaic of scattered bogs having abundant Sphagnum and patches of Dracophyllum, Halocarpus bidwillii, Hebe odora and Donatia novae-zelandiae. Also at the margin of a still, small pond at ca. 1500 m in communities of penalpine shrubs and cushion vegetation, rocky herbfields and Dracophyllum (Horseshoe Basin, Mt. Arthur, Kahurangi Natl. Park). In the alpine zone, for example, at the edge of a tarn with Sphagnum in a mosaic of tussockland and alpine vegetation along with tarns, rills, rocky outcrops and boulderfields (Rainbow Skifield, St. Arnaud Ra., Nelson Lakes Natl. Park, 1360–1480 m). Plants often form very lax, soft, stringy mats, and at times may be submerged, at least after snow melt and after rains.
Comments : Metahygrobiella drucei has somewhat the aspect of a Cephalozia, but the dorsal end of the leaf insertion is transverse and the leaves are more concave, with longer, drawn-out leaf lobes. Plants are characteristically hyaline and whitish below, but the distal parts of leaves, bracts and perianths have a reddish to purplish coloration.
The type of Metahygrobiella cylindrica has leaves that are distinctly succubous on sterile shoots, the angle of insertion being less than 45° to the stem axis. However, the leaves just below the gynoecium are more imbricate and subtransverse. The underleaves are distinct and obvious below the gynoecium.
