Acromastigum inaequilaterum (Lehm. & Lindenb.) A.Evans

Thouvenot, Louis & Müller, Frank, 2021, Contribution to the bryophyte flora of New Caledonia IV. Species new to the country, new localities together with taxonomic notes, Cryptogamie, Bryologie 20 (13), pp. 181-196 : 184

* Acromastigum inaequilaterum (Lehm. & Lindenb.) A.Evans

SPECIMEN EXAMINED. — New Caledonia. South Province, La Foa, Dogny Plateau, 950 m, 21°37’27”S, 165°52’25”E, on dead wood in wet forest, volcano-sedimentary massif, 24.X.2019, Thouvenot NC2669 PC[(PC0699831)].

FURTHER SPECIMEN EXAMINED. — Acromastigum echinatum : New Caledonia. South Province, Yaté, Forêt du Mois de Mai, on trunk in hygrophilous forest, 300 m, 22.VI.1951, Baumann-Bodenheim 13945 PC[(PC0763166)].

COMMENTS

This widely distributed species, taken for quite variable by Evans (1934), was hitherto unreported from New Caledonia. It is easily separated from most of the species included in the subgenus Inaequilatera (Schiffn.) Grolle by a single strong papillose wart on the free wall of the leaf and underleaf cells and the unequal leaf lobes. Furthermore, cell walls evenly thickened separated it from the morphologically close A. echinatum (Gottsche) A.Evans which has thinner walls between prominent trigones. The genus Acromastigum A.Evans is well represented in New Caledonia with a high endemic rate (⅔) and the addition of A. inaequilaterum to this flora increases the number of species and varieties to 17 (Thouvenot 2018). Thus, New Caledonia hosts the richest diversity of this genus behind Malaysia (18 species, Chuah-Petiot 2011) and before Australia (12 species, Brown & Renner 2014).