Heteroscyphus cornutistipulus (Steph.) Thouvenot, comb. nov.

(Fig. 10)

Chiloscyphus cornutistipulus Steph., Species Hepaticarum 6: 303 (Stephani 1922).

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Type: New Caledonia. Franc s.n. (lecto-, here designated, G [“Nlle Calédonie, Mts. Koghis ”, 1.XI.1909, Franc 166, G00069490]!).

FURTHER SPECIMEN EXAMINED. — New Caledonia. South Province, Sarraméa, Dogny, 855 m, on dead wood in wet forest, 26.IX.2016, Thouvenot NC3283 (PC [PC0779841]).

DISTRIBUTION IN NEW CALEDONIA. — Only known from scattered localities in South Province, on dead wood in wet forest at medium elevation.

TOTAL RANGE. — Endemic.

DESCRIPTION

Dioecious.

Habit

Plants medium sized, branching lateral-intercalary; wet shoots 3.50-4.00 mm wide, somewhat complanate,with leaves alternate, horizontally spreading, slightly convex, antical margins free, separated by 2 cortical cell files, shortly decurrent on the stem.

Leaves

1.60-2.20 mm long, 1.20-2.00 mm wide, oval to oblong, slightly longer than wide, apices entire to slightly retuse, widely rounded, margins entire, hardly crenulate.

Cells

Median leaf cells rounded-hexagonal 40-80 µm wide, with thin walls and small to medium acute trigones up to 9 µm wide.

Underleaves

Narrowly to conspicuously connate on single or both sides to the closest leaves, connation 1-6 cells wide, underleaves 3-5 times as wide as the stem, bifid, lobes narrowly triangular, set wide apart, sinus lunate, disc transversely elongate, 1-2 short teeth on both lateral margins.

Gametangia

Androecia and gynoecia on short leafless lateral branches; androecia in spikes made of 6 pairs of bracts very smaller than the normal leaves and inflated; female bracts not seen, female bracteoles 1/3-1/2 bifid, with 1 tooth on both sides; perianths cyathiform, 2.20 mm long, 1.20 mm wide, 3-plicate, plicae rounded, mouth wide, lobate-laciniate, margins roughly toothed; calyptrae 2/3 shorter than the perianths.

COMMENTS

The type specimen has no gametangium, although the packet is annotated “ c. per. ”. A recently collected specimen has androecia and gynoecia (Thouvenot NC3283) and indicates that the species belongs in Heteroscyphus . The fertile plant has smaller trigones but is otherwise vegetatively identical to the type of Chiloscyphus cornutistipulus . Like in H. caledonicus (see under that species), some vegetative characters of H. cornutistipulus (Steph.) Thouvenot, comb. nov. are chiloscyphoid, such as the alternate leaves and the narrow connation of the underleaves. Heteroscyphus cornutistipulus (Steph.) Thouvenot, comb. nov. is close to Chiloscyphus trigonifolius and H. succulentus, but C. trigonifolius is easily separated from H. cornutistipulus (Steph.) Thouvenot, comb. nov. by its smaller size with shoots 1.5-2 mm, strongly involute leaves when dry and the ovatetriangular leaf shape. Furthermore, the androecia are in spikes on normal-leaved shoots, male bracts being quite similar to the normal leaves. Heteroscyphus succulentus differs by its larger size, subopposite leaves, underleaves margins long laciniate instead of short toothed, bulging leaf cells without trigones, and crenulate leaf margins.