Bazzania paucidens (Steph.) H.A.Mill.

Thouvenot, Louis, 2024, A revision of the genus Bazzania Gray (Lepidoziaceae, Marchantiophyta) in New Caledonia with a review of the type specimens, Cryptogamie, Bryologie 20 (6), pp. 117-154 : 141-142

Bazzania paucidens (Steph.) H.A.Mill.

( Figs 1H ; 2C 1 ; 12 )

Phytologia 47 (4): 321 ( Miller 1981). — Mastigobryum paucidens Steph. , Bulletin de l’Herbier Boissier, série 2, 8 (11): 860 ( Stephani 1908c). — Type: New Caledonia, Bernier, Lerat; (holo-, G [New Caledonia, s.d., Bernier 341 p. p., ex herbarium Général Paris, G00066787]!; iso-, PC[PC010817]!; para-, G[Mt Dzumac; IX.1906; Le Rat s.n. PC00282556]!; PC[Le Rat s.n., PC0104030]!; REN[REN000223]!).

Mastigobryum motelayi Steph. , Bulletin de l’Herbier Boissier, série 2, 8 (10): 775 ( Stephani 1908b). — Type: New Caledonia, Motelay, Etesse (lecto-, designated here fide Kitagawa (1970, in sched.), G[New Caledonia, 1896, herbarium Motelay G00048003]!; para-, G[Hienghène; XI.1905; Etesse 15, G00048005]; G[Hienghène, XI.1905; Etesse 16; G00048004]) syn. nov.

Bazzania subintegra (Steph.) L. Söderstr. & A. Hagborg., Phytotaxa 202 (1): 69 ( Söderström et al. 2015). — Mastigobryum subintegrum Steph. , Bulletin de l’Herbier Boissier, série 2, 8 (10): 775 ( Stephani 1908b). —Type: New Caledonia, Le Rat. “sine schedula”, 1907, Le Rat s.n. (lecto-, G[G00067097]!; iso-, G[G00112148]!) syn. nov.

Bazzania subintegra (Steph.) Herzog. Arkiv för Botanik (n. ser.) 3 (3): 46 ( Herzog 1953). Nom. inval. [ICN Art. 41.5; basionym not cited ( Turland et al. 2018; Loiseau et al. 2019)] syn. nov.

Mastigobryum subintegrifolium Steph. ex Paris, Revue bryologique 37: 41 ( Paris 1910a). Nom. inval. [ICN Art. 38.1(a): no description ( Turland et al. 2018; Loiseau et al. 2019)]. — Reference specimen (as Mastigobryum subintegrum ): New Caledonia, Île des Pins; 1908; Placide s.n.; REN[REN000228]! syn. nov.

MATERIAL EXAMINED. — New Caledonia • North Province, Hienghène, Southwest ridge of Mt Colnett ; on dead wood in mesophile forest; 15.IX.1951; Hürlimann 2942 ( PC [ PC0793159 ]) • Panié massif, path between Bwa Téan and Payolé ; on dead wood in mountain wet forest on mica schist bedrock; 1000 m; 9.X.2012; Thouvenot NC 1303 • South Province, Mont-Dore, Mouirange Pass ; on dead wood; 284 m; 1. VI.2015; Metoyer MET064 • Dumbéa, Montagne des Sources ; on bark in wet forest with Araucaria rulei F.Muell. on ultramafic bedrock; 940 m; 21.IX.2016; Thouvenot NC 3444 • Yaté, between Pourina and Pondjémia valley ; on dead wood in primary mesophile forest; 250 m; 3. VI.1951; Hürlimann 2642 ( PC [ PC0793153 ]) • Rivière Bleue natural park, Germain bridge; on bark in mesophile forest, on ultramafic bedrock; 190 m; 5.X.2016; Thouvenot NC 3448 • ibid.; in the vicinity of the Goro oldmine; in wooded scrubland; 242 m; 31.III.2016; Métoyer MET102 • Plaine des Lacs ; photo-xerophilous forest on laterite soil; 305 m; 1.X.2019; Thouvenot NC 3462 • Païta, Mt Mou, Pic des Mousses ; on bark; c. 1200 m; 23.VIII.1950; Hürlimann 5699 ( PC, as Bazzania franciana ) • Thio, Grand Borindi, Nému Kwéré Chékwa ; on bark and dead wood in dry forest on ultramafic bedrock; 193 m; 22.X.2016; Thouvenot NC 3425, NC3429 .

DISTRIBUTION IN NEW CALEDONIA. — Frequent on bark and dead wood in both provinces of Grande Terre, at any elevation.

TOTAL RANGE. — Endemic to New Caledonia.

DESCRIPTION

Plants

Medium sized, rather rigid, creeping in dense wefts or among other bryophytes, shoots 2-2.5(-3.0) mm wide, terminal branching common, pseudo-dichotomous, ventral-intercalary branches flagelliform.

Leaves

Loosely imbricate,spreading at right angle,complanate and hardly convex in wet condition, deflexed when dry, asymmetrically ovate-truncate to oblong, (0.65-)0.90-1.70(-1.90) mm long, (0.50-)0.75-1.00(-1.20) mm wide near bases, 0.35-0.50 mm below apices, length to width ratio 1.0-1.6(-1.8); dorsal margins nearly straight to widely arched, ventral margins nearly straight to slightly concave,shortly rounded at base, border sparingly and unevenly denticulate in upper parts; apices obliquely truncate, with three wide triangular lobes ending in sharp points, small to medium, 1-7 cells long, separated by lunate to obtuse sinus.

Leaf cells

Relatively homogeneous, median cells rounded to oblong, 16-25 µm wide, 16-42 µm long, with thin walls and conspicuous trigones, usually bulging; marginal cells smaller in

1-2 files, rounded to oblate, thick-walled, 12-16 µm wide, 20-24 µm long; cell size gradually increasing toward the base without defining any distinct subvitta, basal cells up to 45 µm wide and 75 µm long.

Underleaves

Patent, recurved, obliquely inserted, positioned close to the leaf bases and usually narrowly connate on both sides, reniform to transversely elongate, 0.45-0.65(-1.00) mm wide, 0.30-0.50(-0.80) mm long, 2-2.5 times wider than the stem; lateral margins repand or convex, unevenly denticulate; apex slightly convex to straight, margins repand to shallowly lobulate, more or less obtusely denticulate by protruding hyaline cells; hyaline border narrow to wide, typically decurrent up to the bases, thin-walled cells usually in 2-5(-8) rows, inner cells oblong to elongate, thin-walled with usually large trigones (Description after the types of Mastigobryum paucidens ).

NOTES

Bazzania paucidens is distinctive by: 1) compact leaf shape, usually ovate-oblong to widely ovate, obliquely truncate, less than 1.6 times longer than wide, shortly 3-lobate; 2) leaf cells thin-walled with usually bulging trigones, gradually larger toward base without forming a distinct subvitta; 3) underleaves wider than long; 4) underleaf border conspicuously hyaline, usually 2-5 cells wide; and 5) underleaf apices repand-lobulate, shallowly denticulate. It is quite close to B. franciana or B. adnexa . For distinctive features, see the notes under these species.

Bazzania paucidens is quite variable, likely linked to ecological conditions, since the strongest forms are growing in cloud forests of the central range, while the weakest forms are found at the lowest elevations; but they share an overall shape of leaves, widely ovate with obliquely truncate apices shortly tridentate, median cells with usually trigones and limbate underleaves with repand margins; the usually faint denticulation is sharp and obvious only in the strongest forms.

Among the specimens at G, only two could be observed by Stephani before he published the new species. In the protologue, Stephani cites two collectors, Bernier and Le Rat. The first syntype at G[G00066787], collected by Bernier, was formally designated by Stephani as the type on his drawing 291 (unpublished Icones, nr 007138 [G]). Therefore, it is the holotype.Regarding the second, among the specimens collected by Le Rat, only G00282559 was collected earlier 1908 and can therefore be a syntype. Morphological differences between the type specimens involve leaf shapes that can be falcate, ovate in basal half and oblong-lingulate above, to widely ovate with arched antical bases and not falcate. The two types are figured by Stephani in Icones, nr 291, so both forms are included in the variability of the species. This species has some similarity with Bazzania adnexa ; see comments below the latter.

The type and reference specimens of Bazzania subintegra do not show a significant difference with B. paucidens . The name Mastigobryum subintegrifolium was used by E.G. Paris in his paper reporting the bryophyte collections of Mrs Louise Le Rat in Île des Pins in 1908 ( Paris 1910a). As the single voucher specimen from Île des Pins present in his herbarium (REN) is labelled Mastigobryum subintegrum , I believe that “ subintegrifolium ” must be regarded as a lapsus calami.

Mastigobryum motelayi was synonymized with Bazzania marginata by Kitagawa (1973). But the type at G, designated by this author (1970, in sched.), fit the distinctive features of B. paucidens , namely the thin-walled leaf cells, with bulging trigones. Here I consider Mastigobryum motelayi as a synonym of Bazzania paucidens .

Figures

FIG. 1. — Leaves and underleaves drawn at the same scale from type specimens of New Caledonian Bazzania Gray species: A, Mastigobryum leratii Beauverd ex Steph.; A1, underleaf; A2, leaf (both from isotype REN000232); A3, leaf (lectotype G00067047); B, M. bescherellei (Steph.) Steph. (lectotype G00066912); B1, B4, underleaves;B2, B3, leaves;C, M.consociatum Steph.(syntype PC0101765); C1, C2, underleaves;C3, leaf;D, M.francanumSteph.(lectotype G00066893); D1, D2, D5, leaves; D3, D4, underleaves; E, M. dognyense Steph. (lectotype G0011718); E1, leaf; E2, E3, underleaves; F, M. incrassatum Steph. (isolectotype PC0101851); F1, F2, underleaves; F3, F4, leaves; G, M. marginatum Steph. (lectotype G00066911); G1, leaf; G2, underleaf; H, M. paucidens Steph. (holotype G00066787); H1, leaf; H2, underleaf; I, M. quadratum Steph. (lectotype G00066891); I1, leaf; I2, I3, underleaves. Scale bar: 200 µm.

FIG. 2. — Leaves and underleaves drawn at the same scale from type specimens of New Caledonian Bazzania Gray species:A, Mastigobryum serrifolium (Steph.) Steph.(syntype G00282526); A1, underleaf; A2, leaf; B, M. bernieri f. falcifolium Steph. (lectotype G00282530); B1, leaf;B2, underleaf;C, M. subintegrum Steph. (isotype G00112148); C1-C3 underleaves; C4-C6 leaves; D, M. pectinatum Lindenb. & Gottsche (isotype G00282552); D1, D5, leaves; D2-D4 underleaves; E, Herpetium australe Mont. (lectotype PC0769355); E1, underleaf; E2, leaf; F, Jungermannia tridens Reinw., Blume & Nees (isotype G00064266); F1, underleaf; F2, F3, leaves. Scale bar: 200 µm.

FIG. 12. — Bazzania paucidens (Steph.) H.A.Mill.: A, C, G, J, leaves; B, D, F, H, I, underleaves; E, median leaf cells; K, basal leaf cells. A-D, G, J, from Thouvenot NC3225; E, H, K, from Thouvenot NC3444; F, I, from Metoyer MET068. Scale bars: A-D, F-H, 200 µm; E, I, K, 20 µm; J, 100 µm.