Heteroscyphus deplanchei (Steph.) Schiffn.

Thouvenot, Louis, 2023, A taxonomic revision of the Lophocoleaceae Vanden Berghen (Marchantiophyta) of New Caledonia, Cryptogamie, Bryologie 20 (1), pp. 1-60 : 21-24

Heteroscyphus deplanchei (Steph.) Schiffn.

( Fig. 11 )

Oesterreichische Botanische Zeitschrift 60: 172 ( Schiffner 1910). — Chiloscyphus deplanchei Steph. , Species Hepaticarum 3: 203 ( Stephani 1907).

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Type: New Caledonia. Deplanche s.n. (holo-, G[G00069487]!).

Lophocolea heteromorphis Steph. , Species Hepaticarum 6: 275 ( Stephani 1922). — Chiloscyphus heteromorphus (Steph.) J.J.Engel & R.M.Schust. , Nova Hedwigia 39: 416 ( Engel & Schuster 1984 [1985]).

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Type: New Caledonia. “ Lerat ” s.n. (holo-, G [“ Lophocolea heteroformis (sic) n.sp., Dent de St Vincent , juillet 1909 ”, Le Rat s.n., G00112505 ]!) syn. nov.

FURTHER SPECIMENS EXAMINED. — New Caledonia. North Province, bank of the upper Diahot, on siliceous sand, 430 m, 31.VIII.1951, Hürlimann 2901 ( G); Hienghène, Pwé Hwa Wéc river , on rocks in creek bank, 630m, 22.IX.2019, Thouvenot NC2773 ( PC [ PC0779850 ]); South Province, Dumbéa, Pic des Sources, s.d., Le Rat 265a (G); Mt. Mou, VII.1904, Le Rat s.n. (G); Pourina valley affluent, 150 m, on dead branch in mesophilous forest, 4.VI.1951, Hürlimann 2655 (GOET); Yaté,Wé Toa,on stump bark in rain forest, 500 m, 8.IX.2019, Thouvenot NC2852 (PC[PC0779849]); Plaine des Lacs, on rocks in lowland wet forest, 260 m, 6.X.2016, Thouvenot NC2441; Pic du Grand Kaori, on rocks covered with humus in lowland wet forest, 480 m, 4.X.2016, Thouvenot NC2433; Lac Chakéké, on damp soil in creek bank, 425 m, 4.X.2019, Thouvenot NC2729; “Rivière Bleue, forêt vallicole, épixyle”, 160 m, 15.V.1970, Schmid 148 as “ Chiloscyphus physanthus ” (PC[PC0146342]); Mont Dore, Mouirange,on dead wood in rain forest, 550 m, 16.IX.2019, Thouvenot NC2818; Rivière Blanche, Rivière Bleue Natural Park,sentier des Cochons, 556 m, 17.IX.2019, Thouvenot NC2859; MacKee 30813 as “ Chiloscyphus caledonicus ” (PC[PC0737581]).

DISTRIBUTION IN NEW CALEDONIA. — Fairly frequent in the ultramafic massif of South Province, rare in siliceous massifs of North Province, at low to medium elevation (collected from 150 to 1000 m) on dead wood or tree stumps in rain forest.

TOTAL RANGE. — Endemic.

DESCRIPTION

Dioecious.

Habit

Large plants, shoots 3.00-5.00 mm wide, usually single, lateralintercalary branching rare; leaves firms, obliquely assurgent dorsally, canaliculate-convex, spreading at right angle to the stem, subopposite, reaching the dorsal mid-line of the stem and usually confluent.

Stem

300 µm wide, with 60-100 homogeneous thin-walled cells on transverse section.

Leaves

Mostly ovate-lingulate, wider at bases, 1.80-2.70 mm long, 1.20-2.00 mm wide at base, margins entire as well as the apices that are widely rounded to obliquely truncate to retuse with rounded angles, in some secondary shoots a few or many leaves may be emarginate to shortly bifid with 1-2 acute short lobes.

Cells

Leaf cells 40-60 µm wide, thin walled with strong nodulose trigones, not confluent.

Underleaves

Reniform, 8-10 times wider than the stem, 0.80-1.50 mm long, 1.80-2.50 mm wide, connate on both sides to the ventral bases of the nearest leaves, apices bifid to quadrifid, lobes narrowly acuminate from triangular bases, sinus widely lunate, margins long toothed-laciniate all around, teeth narrowly acuminate, at times furcate.

Gametangia

Androecia and gynoecia at the apices of very short lateralintercalary leafless branches; androecia small, up to 1 mm long, in spikes made of four pairs of bracts, bracts inflate concave with truncate apices, 3-toothed, 400 µm long, 300 µm wide in situ, bracteoles shortly bifid, 250 µm as wide as long; gynoecia with two series of female bracts and bracteoles, more or less similar, obovate in outline, apices lobate, more or less deeply incised, margins toothed to laciniate, bracts 3.00 mm long, 2.50 mm wide, bracteoles smaller, 2.25 mm long, 2.00 mm wide, perianths cyathiform, without plicae or shallowly plicate in upper part, 3.50 mm long, 2.80 mm wide, mouth deeply laciniate, calyptrae very shorter than the perianths.

COMMENTS

Stephani (1907) described Chiloscyphus deplanchei with leaf apices “ truncato-rotundo vel emarginatulo ”. The scarce shoots of the holotype at G fit this description, but examination of additional material shows that this character is rather variable. The largest forms have leaves with essentially entire, rounded apices, and strongly laciniate underleaves with the apical lobes hardly distinguishable from the lateral processes. But mostly, the plants have long shoot portions with acute or shortly bifid leaf apices and other portions, mainly terminal, with entire, rounded leaves. In rare cases almost all leaves are acute or bifid, with a few entire, rounded leaves being restricted to the shoot apices. Later, Stephani (1922) describes Lophocolea heteromorphis with leaves “ inaequaliter bifida vel solum apiculata ”. The type specimen seen at G shows mostly such leaves but leaves with entire rounded apices occur on some shoots. Underleaves may be smaller, less wide and less divided, but here too there are underleaves like in Chiloscyphus deplanchei . In fact, all other features are very similar: habit, shoot width, stem anatomy, cell size and shape, gametangia and most of the underleaf characters. As the leaf apex shape is the only diverging character, varying along a continuum between two extreme patterns represented by Chiloscyphus deplanchei and Lophocolea heteromorphis , it can be asserted that they represent variants of the same species.

Heteroscyphus deplanchei superficially looks like H. succulentus (Gottsche) Schiffn. (see below), which has a similar leaf shape, but the latter can be distinguished by the fleshy, translucent, dorsally free leaves with a more lax areolation, and underleaves long toothed rather than laciniate and the cells without trigones. Furthermore, the male bracts of H. succulentus are rounded truncate and the perianth is 3-plicate with a toothed mouth ( Piippo 1985). Heteroscyphus deplanchei might also be confused with H. supinopsis . For the distinctive characters, see below the relevant paragraph.

Although Stephani described the gynoecia, the type material in G is sterile. The above account of the gametangia, which contains the first description of the androecia, is based on material collected by the author in 2019.

Figures

FIG. 11. — Heteroscyphus deplanchei (Steph.) Schiffn.: A, shoot portion, ventral view; B, leaf cells; C, K, leaf apices diversity; D, leaf; E, shoot portion, dorsal view; F, female bract; G, androecium, dorsal view; H, pair of male bracts and bracteole, dorsal view; I, leaf and underleaf; J, perianth open with calyptra (ca). A, B, drawn from the holotype of Chiloscyphus deplanchei Steph. (G00069487); C-F, J, from Thouvenot NC2852; G, H, from Thouvenot NC2773; I, K, from the type of Lophocolea heteromorphis Steph. (G00112505). Scale bars: A, C-F, I-K, 1 mm; B, 50 µm; G, 400 µm; H, 200 µm.