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

description: Heteroscyphus confertus (Steph.) Thouvenot
(Fig. 9)
Cryptogamie, Bryologie 39 (3): 365 (Thouvenot et al. 2018). — Chiloscyphus confertus Steph., Species Hepaticarum 6: 305 (Stephani 1922).
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Type: New Caledonia. Franc s.n. (lecto-, here designated, G [“ Mts. Koghis, 600 m ”, 1.XI.1909, Franc 210, G00069492]!; syn-, PC [“ Mts. Koghis, 300 m ”, 1911, Franc s.n., PC0101951]!).
Heteroscyphus rotundiphyllus (H.A.Mill.) Thouvenot, Cryptogamie, Bryologie 39 (3): 365 (Thouvenot et al. 2018). — Chiloscyphus rotundifolius Steph., Species Hepaticarum 6: 313 (Stephani 1922), nom. illeg. — Chiloscyphus rotundiphyllus H.A.Mill., Phytologia 47: 321 (Miller 1981).
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Type: New Caledonia. “ Lerat ” s.n. (lecto-, here designated, G [New Caledonia, “ Dent de St Vincent, VII 1909 ”, Le Rat 189 (herb. Thériot), G00069432]!) syn. nov.
FURTHER SPECIMENS EXAMINED. — New Caledonia. North Province, Hienghène, Ouaième Rocks, on twigs in mountain scrubland, on metamorphic bed rock, 982 m, 22.IX.2019, Thouvenot NC3285; South Province, “ near Nouméa ”, s.d., Le Rat s.n. (PC [PC0167665]); Yaté, Rivière Bleue natural Park, Pourina trail, on bark in a wet forest clearing, 670-695 m, 20.IX.2016, Thouvenot NC2477; Païta, Mont Mou, on twigs in cloud forest, 1219 m, 17.IX.2016, Thouvenot NC1971; Humboldt massif, along the trail to the hut, on bark in cloud forest, 1205 m, 30.IX.2008, Thouvenot NC1832; NC1851.
DISTRIBUTION IN NEW CALEDONIA. — Scattered in both provinces of the main island, Grande Terre, collected from 300 to 1200 m, where it grows usually on barks in wet scrublands and open forests, more rarely on rocks in creek banks.
TOTAL RANGE. — Endemic
DESCRIPTION
Dioecious.
Habit
Plants large, shoots 3.50-4.00 mm wide when flattened, soft and fragile; shoots as a whole convex in ventral view and dorsally canaliculate, at most tube like and the ventral leaf faces exposed with conspicuous underleaves; leaves dorsally assurgent, undulate from back to front with the antical half convex, facing the corresponding antical half of the opposite leaf and the postical half concave, leaves densely imbricate, subopposite, the dorsal margins of opposite leaves confluent on stem back.
Leaves
Orbicular, symmetrical, up to 2.50 mm as wide as long, apices shortly bifid, at times entire, sinus lunate, lobes erect to connivent, triangular acuminate, margins entire, crenulate or minutely toothed.
Cells
Leaf cells rounded hexagonal, 25-50 µm wide, with medium to large bulging trigones, becoming longer towards bases.
Underleaves
Large, up to 5 times the stem width, widely connate to the nearest leaves on both sides, rounded to slightly reniform, 0.70-1.40 mm as wide as long, ¹⁄10-1/3 bifid, sinus obtuse to right angled, lobes triangular acuminate to lanceolate-linear, both margins with few to numerous small teeth.
Gametangia
At the end of short leafless lateral-intercalary branches; gynoecia with bracts lobate, toothed, half long as the perianth, bracteoles small, toothed, perianths cyathiform, 3.00 mm long, 1.70-2.50 mm wide, with 5-6 rounded plicae, upper parts lobate, margins toothed-ciliate, calyptrae small, 0.6-0.7 times the perianth length; androecia in curved spikes, small, 2-4 pairs of bracts, bracts oval with retuse apices and 1-2 unicellular teeth, margins with a few slime papillae, antheridium stalk cells two ranked.
COMMENTS
Stephani (1922) published Chiloscyphus confertus and C. rotundifolius with nearly the same description. Checking the type specimens at G, it was not possible to find clear distinctive features and the differences between the corresponding drawings by Stephani (icones nr 001925 and 001978) are parts of the variability in leaf and underleaf marginal ornamentations. Fresh specimens also show variations in leaf apices, leaf and underleaf ornamentations in the same plants so that they could be equally assigned to both species. As a result, they are considered as synonyms. As both names were published at the same date and as the name Chiloscyphus rotundifolius was illegitimate (Turland et al. 2018: art 11.4), H. confertus is the correct name.
This species can be separated from other New Caledonian species with orbicular leaves, such as Heteroscyphus aselliformis and H. kanakensis, by the homomallous shoots. In addition, H. aselliformis is readily separated from H. confertus by asymmetrical leaves and leaf apices with two long filiform lobes, and H. kanakensis by stronger texture (not fragile), smaller plant size with shoots up to 3 mm wide and leaves to 1.6 mm long, and by the entire or crenulate leaf margins and rounded apices. It also shares many features with Heteroscyphus menziesii (Mitt.) J.J.Engel, from New Zealand, but the latter is a smaller species, the leaves have a conspicuous lip like connation at back, leaf apices are 2-toothed with sublinear short teeth instead of clearly bifid, and the underleaf lobes are thinner and forward directed. A specimen of H. confertus collected in New Caledonia by Le Rat and kept in PC (PC0167665) is a doubtful type, contrary to the assumption of Thouvenot et al. (2018), since the locality differs from that of the type in G. Moreover, the date of collecting is lacking.
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 18-20, DOI: 10.5252/cryptogamie-bryologie2023v44a1, http://zenodo.org/record/7822577