Chiloscyphus trigonifolius Steph.

Thouvenot, Louis, 2023, A taxonomic revision of the Lophocoleaceae Vanden Berghen (Marchantiophyta) of New Caledonia, Cryptogamie, Bryologie 20 (1), pp. 1-60 : 7-8

Chiloscyphus trigonifolius Steph.

( Fig. 1 )

Species Hepaticarum 6: 316 ( Stephani 1922).

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Type: New Caledonia. “ In summo Mt. Dent de St Vincent , 1425 m ”, VII.1909, L. Le Rat 101 (lecto-, here designated, G [ G00069423 ]!; isolecto-, PC [ PC0167659 ]!, REN [herb. E. G. Paris]!).

Chiloscyphus trigonifolius Steph. ex Paris, Revue bryologique 37: 129 ( Paris 1910), nom. inval. (no description). — Material: REN[herb. E. G. Paris] syn. nov.

FURTHER SPECIMEN EXAMINED. — New Caledonia. South Province, in the vicinity of Nouméa, 1909, Le Rat s.n., determinavit Stephani as “ Chiloscyphus cornutistipatus ” ( PC [ PC0167669 ]).

DISTRIBUTION IN NEW CALEDONIA. — Only known from the type locality, a remote place hard to reach, and one further historic specimen without precise location.

TOTAL RANGE. — Endemic.

DESCRIPTION

Dioecious.

Habit

Plant medium, moist shoots 1.00-2.00 mm wide, 2.50 mm wide when flattened; leaf bases dorsally assurgent, strongly convex, masking the stem, the leaves distally curving downward, leaves second, imbricate, alternate, dorsally free, separated by a two ranked band of cortical cells.

Leaves

Ovate-triangular to rounded in outline, wider than long, 0.80-0.90 mm long, 1.10 mm wide at base, entire margined, apices rounded, margins convex, slightly crenulate by the prominent marginal cells.

Cells

Leaf cells 20-25 µm wide, thin walled with small acute trigones.

Underleaves

Small, 2 times the stem width, 0.60 mm long, 0.40-0.60 mm wide, connate to one adjacent leaf, bifid up to mid-length, sinus lunate, lobes lanceolate, acuminate to obtuse, upward directed, disc margins with 1-2 short teeth.

Gametangia

Androecia in series of numerous bracts and antheridia (10 pairs) inserted between normal-leaved sections of the main stems or at the end of long leafy branches; male bracts similar in size to vegetative leaves but with inflated dorsal base including antheridia; gynoecia not seen.

COMMENTS

The alternate leaves, unilateral connation of underleaves with leaves, little differentiated male bracts and androecia on elongate shoots separate Chiloscyphus trigonifolius from Heteroscyphus while the entire leaves and, again, little differentiated male bracts with saccate dorsal base distinguish it from most Lophocolea . Unfortunately, gynoecia are unknown in C. trigonifolius and definitive evidence for its placement in Chiloscyphus vs Lophocolea is therefore lacking. But, since all known characters match Chiloscyphus , we conservatively keep the species in this latter genus pending further collections of female plants.

In the original publication of Chiloscyphus trigonifolius, Stephani mentions Franc as collector, but the label of the original material of C. trigonifolius in G mentions Louise Lerat as the collector. In the checklist of the New Caledonian liverworts, Thouvenot et al. (2011) stated that the identity of Chiloscyphus trigonifolius Steph ex Paris was unclear since Paris did not give any description of this taxon. The specimen kept in the herbarium of E. G. Paris at REN have been checked; its label is identical to the one in G; moreover, the plant exactly matches Stephani’s diagnosis and drawing of C. trigonifolius and therefore constitutes a duplicate of the material used by Stephani to define his new species. A letter from Stephani (9 Febr. 1910) (Rennes 1 University Library) reports Chiloscyphus trigonifolius as a new species, cited as “nr 101”, among the material collected by Mr. and Mrs. Le Rat and sent to Stephani by Paris. This confirms that the type is not from Franc and that the specimen at REN must be an isolectotype.

Heteroscyphus cornutistipulus is close to Chiloscyphus trigonifolius , with leaves and underleaves being superficially similar. It differs essentially by: 1) shoots complanate; 2) leaves slightly convex and horizontally spreading; 3) larger sizes in all dimensions: shoot width, leaf length and width, cell diameters, trigones width; and 4) androecia on very short ventral branches. Furthermore, the leaves are ovate oblong, longer than wide, instead of widely ovate, wider than long in the latter. Out of New Caledonia, Heteroscyphus furcistipulus , endemic to New Zealand, is similar to C. trigonifolius in all vegetative characters ( Engel & Glenny 2019), but the former has very distinctive androecia of heteroscyphoid type, with 3-8 pairs of ventricose bracts on leafless ventral branches that are hidden under the normal leaves, while male bracts of C. trigonifolius are relatively shortly ventricose at the base of large rounded flat lamina and are set in spikes at the end of normal leaved branches or main shoots, or inserted inside main shoot portions; androecia of heteroscyphoid type are lacking. Furthermore, H. furcistipulus is calcicolous since C. trigonifolius was found in ultramafic massifs.

Figures

FIG. 1. — Chiloscyphus trigonifolius Steph.: A, leaf cells; B, leaves and underleaf in ventral view; C, shoot portion in ventral view; D, androecium; E, leaves and underleaf in dorsal view. A, C, drawn from the lectotype (G00069423); B, D, E, drawn from the isolectotype (PC0167659). Scale bars: A, 20 µm; B-E, 500 µm.