Bazzania quadratistipula H.A.Mill.

Bazzania quadratistipula H.A.Mill. View in CoL

( Figs 1I View FIG ; 13 View FIG 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 .