Bazzania quadratistipula H. A. Mill.

Bazzania quadratistipula H.A.Mill. (Figs 1I; 13 A-G) Phytologia 47: 321 (Miller 1981). — Mastigobryum quadratum Steph., Species Hepaticarum 6: 477 (Stephani 1924). Non Mastigobryum quadratum Colenso 1886. — Type: New Caledonia, Le Rat s.n. (lecto-, designated here, G [“In jugo Dogny (1050 m)”, s.d., L. Le Rat s.n. G00066891]!) Mastigobryum quadratum Steph. ex Paris, Revue bryologique 37: 131 (Paris 1910b). nom. nud. (Reference specimen: REN[New Caledonia, South Province, Mt Mou; VII.1909; Le Rat s.n. REN000224]!). DISTRIBUTION IN NEW CALEDONIA. — Only known by a few old collections in South Province. TOTAL RANGE. — Endemic to New Caledonia. DESCRIPTION Plants Medium sized, soft and fragile, creeping in dense wefts of interwoven stems and branches; moist shoots 2-2.5 mm wide, stems 0.22-0.32 mm wide; pseudo-dichotomous terminal branching rare, often asymmetrical, ventral-intercalary branching common, both flagelliform and normal leaved, axillary to underleaves. Leaves Imbricate, spreading, hardly convex, deflexed when moist or dry, ovate-oblong to ovate-ligulate, asymmetrical, with the sub-apical width about half the basal, 1.00- 1.60 mm long, 0.50-0.75 mm wide near bases, 0.30-0.40 mm below apices, length-width ratio 1.7-2.0; both margins crenulate-denticulate to dentate in upper part, dorsal margins widely arched in basal 1/3-2/3, straight in upper part, the ventral sub-straight to slightly concave; apices unevenly and coarsely 3-lobate, lobes triangular acute or obtuse, margins denticulate. Cells Pattern rather homogenous, except a poor subvitta in a short basal part; upper cells rounded-quadrate to oblong, 20-30 µm wide, 20-36 µm long, thin-walled, with large bulging trigones; marginal cells smaller, oval oblate; basal cells oblong to rectangular, up to 40 µm wide and 60 µm long, thin-walled with very large trigones usually confluent. Underleaves Patent, transversally inserted, positioned near the leaf bases on one side of the stem and unconnected, flat to slightly concave, sub-quadrate to longer than wide, 0.40-0.50 mm long, 0.30-0.50 mm wide, as wide as the stem or slightly more; underleaf outline variously dissected in a same plant, at most strongly dentate all around the free margins, but the lateral margins may also be repand, entire or with a few teeth at bases; apex various, usually lobate, lobes acute to obtuse, often secondarily toothed; underleaf areolation like in the leaves, without hyaline border (Description after the lectotype at G and the reference specimen at REN). NOTES Bazzania quadratistipula is a relatively small and soft species which is readily distinguished by its interwoven habit due to predominant ventral intercalary branching. In addition, specific characters include: 1) small quadrate underleaves; 2) underleaf margins variable, either strongly toothed to lobed all around, or simply repand, dentate, denticulate, or entire; 3) leaves falcate-lingulate, fragile, dentate-denticulate in upper part; 4) leaf apices coarsely 3-lobate, lobes triangular acute usually denticulate; and 5) all leaf cells with large bulging trigones, becoming gradually larger below. Paris (1910b) conservatively published the name Mastigobryum quadratum after his correspondence with Stephani (31.III.1910, unpublished, Rennes University Library), but without any description. The specimen kept at REN that matches the locality and collector quoted in Paris (1910b) can be a reference specimen for the invalid name M. quadratum Steph. ex Paris, but locality and collector of the type of M. quadratum Steph. at G are different; so, the specimen at REN cannot be a part of the type material for B. quadratistipula.