Heteroscyphus diestianus (Sande Lac.) Piippo

Thouvenot, Louis, 2023, A taxonomic revision of the Lophocoleaceae Vanden Berghen (Marchantiophyta) of New Caledonia, Cryptogamie, Bryologie 20 (1), pp. 1-60 : 24-26

Heteroscyphus diestianus (Sande Lac.) Piippo

( Fig. 12 )

Acta Botanica Fennica 131: 165 ( Piippo 1985). — Chiloscyphus diestianus Sande Lac. in Miquel, Annales Musei Botanici LugdunoBatavi 1: 296 ( Sande Lacoste 1864).

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Type: Indonesia. Banca, in m. Maras, 2000’; van Diest s.n., not seen.

SPECIMEN EXAMINED. — New Caledonia. South Province, Mont Humboldt, c. 1600 m, 21.VIII.2003, Müller NC803 ( DR and author’s private herbarium).

DISTRIBUTION IN NEW CALEDONIA. — Only found in South Province at the highest elevation.

TOTAL RANGE. — Also occurring in Borneo, Indonesia, Malaysia and Papua New Guinea ( Piippo 1993).

DESCRIPTION

Based on the New Caledonian specimen. Further descriptions and illustrations in Piippo (1993).

Habit

Plants fleshy, rather swollen, medium sized, shoots 3.00 mm wide, usually single, lateral-intercalary branching rare; leaves subopposite, thin, imbricate, dorsally obliquely assurgent at angle of ± 45°, laterally spreading at right angle to the stem, the dorsal segments convex, the ventral strongly concave, dorsal margins not reaching the mid-line of the stem, not fused to the opposite leaf margin, the dorsal bases not decurrent.

Leaves

Ovate, 1.20-1.40 mm long, 0.90-1.20 mm wide at bases, 0.45-0.60 mm wide below apices, dorsal bases expanded, usually toothed, dorsal margins nearly right above the bases, entire or with a few teeth near base, ventral margins entire, arched and recurved in part making a conspicuous concavity on dorsal surface, apices rounded, often sinuous to angulate, apical margin entire; teeth small to conspicuous, from linear, 1-3 cells long, to triangular, 2-3 cells wide at base, 4-5 cells long, the teeth cells rounded.

Cells

Leaf cells rounded to oval, 33-60 µm long, 25-37 µm wide, very thick-walled with one pit on each side, trigones fused to the walls, marginal cells smaller, cells often bulging.

Underleaves

Inserted in a deep sinus, 5-9 times wider than the stems, widely reniform, 0.55-0.80 mm long, 1.10-1.80 mm wide, very narrowly connate on both sides to the nearest leaves, free margins abaxially recurved giving a swollen appearance to the underleaves, apices essentially entire but somewhat undulate, with a few remote teeth or none, teeth like on the leaves but smaller.

Gametangia

Not seen.

COMMENTS

Heteroscyphus diestianus is easily recognized by the large swollen underleaves, widely reniform, as wide as the leaves, the teeth restricted to the base of leaf dorsal margins and the strongly thickened cell walls. Its presence in New Caledonia is documented by a single specimen collected in 2003, in the vicinity of one of the highest summits of the country.

Figures

FIG. 12. — Heteroscyphus diestianus (Sande Lac.) Piippo: A, shoot portion, ventral view; B, dorsal face of leaf, with reflexed ventral margin; C, underleaf, adax- ial face (dorsal view); D, F, H, leaves, ventral view; E, cells; G, appendices in basal segment of dorsal leaf margin. All drawn from Müller NC803. Scale bars: A-D, F, H, 500 µm; E, 50 µm; G, 100 µm.