Heteroscyphus giganteus Hurl.
Creators: name: Thouvenot, Louis
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Marchantiophyta
Jungermanniopsida
Jungermanniales
Lophocoleaceae
Heteroscyphus
Heteroscyphus giganteus

description: Heteroscyphus giganteus (Steph.) Hürl.
(Fig. 14)
Bauhinia 12: 114 (Hürlimann 1998). — Chiloscyphus giganteus Steph., Species Hepaticarum 6: 307 (Stephani 1922).
—
Type: New Caledonia. Franc s.n. (lecto-, here designated, G [“ Mt. Mou, 1200 m ”, 1.XI.1908, Franc s.n., G00069481]!; isolecto-, G [G00283069]!).
Chiloscyphus giganteus fo. minor Herzog, Arkiv för Botanik, n.s. 3 (3): 46 (Herzog 1953).
—
Type: New Caledonia. 8.VII.1949, Selling B126 p.p. (holo-, S).
FURTHER SPECIMENS EXAMINED. — New Caledonia. North Province, Hienghène, Ouaïème rocks, on trunks in mountain shrubland, 854 m, 22.IX.2019, Thouvenot NC2798; South Province, Mont Dore, Prony, Baie du Carénage, 16.XI.1950, Guillaumin 8579a (GOET); Yaté, Forêt du Mois de Mai, 235 m, 23.X.2012, Thouvenot NC1008; Yaté, Goro, 200-310 m, 31.III.2016, Metoyer 122; Yaté, Pic du Grand Kaori, on bark, 472 m, 4.X.2016, Thouvenot 2435 (PC [PC0779852]); Bouloupari, Mt. Do, on bark, 960 m, 15.IX.2016, Thouvenot NC2470.
DISTRIBUTION IN NEW CALEDONIA. — Frequently found in South Province, rarer in North Province, at low to medium altitudes (collected from 0 to 1250 m), Heteroscyphus giganteus grows on barks in various vegetation types, from photo-xerophilous to cloud forests, primary or secondary mountain scrublands, gallery forests.
TOTAL RANGE. — Endemic.
DESCRIPTION
Dioecious.
Habit
Plants light green, large, fragile, 4.00 mm wide in fresh condition, 6.00-7.00 mm when flattened, simple or sparsely furcate, branching lateral-intercalary, leaves subopposite, dor-sally assurgent, longitudinally undulate with the ventral half concave and the dorsal convex, thus the shoots are swollen.
Leaves
Large, rounded, more than 3.00 mm wide, margins entire, apices emarginate with short lunate sinus and two short lobes triangular to rounded.
Cells
Leaf cells 30-56 µm wide, thin walled, hexagonal with rounded lumina and large truncate trigones.
Underleaves
Reniform, 1.00- 1.60 mm long, 1.00-2.00 mm wide, bilaterally connate to the nearest leaves, deeply bifid, the lobes lanceolate, simple or furcate, widely divergent, lateral margins usually with at last two long narrow teeth or laciniae.
Gametangia
At the end of very short leafless lateral shoots; gynoecia 2.75 mm long, involucres strongly inflate, bracts 2.00 mm long, 1.75 mm wide, ovate in outline, deeply and asymmetrically bifid, margins coarsely toothed, teeth large and triangular, bracteoles 2.00 mm long, 1.50 mm wide symmetrically bifid, sinus half-length deep, lateral margins coarsely toothed, young perianths cyathiform, deeply multifid, lobes ovate-triangular sparsely and coarsely toothed. Androecia in curved spikes, made of about 5 pairs of bracts.
COMMENTS
This species is easily separated from all other New Caledonian Lophocoleaceae by the combination of the following characters: 1) large shoots, 6-7 mm wide; 2) large leaves rounded concave and dorsally assurgent so that the shoots seem inflate; 3) margins entire; 4) apices emarginate with small lunate sinus; 5) leaf cells with large truncate trigones; and 6) underleaves bifid with lobes widely divergent, and 2-3 laciniae on each lateral margin. Fresh fertile specimen shows the dioecious condition and allows to describe the gynoecium. Heteroscyphus giganteus superficially looks like H. aselliformis and H. confertus; to distinguish characters see under these species. The size of C. giganteus fo. minor is like in H.confertus, but underleaves and trigones match those of C. giganteus. Consequently,it is not necessary to separate this form.
description: Published as part of Thouvenot, Louis, 2023, A taxonomic revision of the Lophocoleaceae Vanden Berghen (Marchantiophyta) of New Caledonia, pp. 1-60 in Cryptogamie, Bryologie 20 (1) on pages 26-28, DOI: 10.5252/cryptogamie-bryologie2023v44a1, http://zenodo.org/record/7822577