* Riccia hasskarliana Steph.

SPECIMEN EXAMINED. — New Caledonia. South Province, Sarraméa, along the hiking trail from Sarraméa to the Plateau de Dogny, 21°38’S, 165°52’E, on wet open soil along the trail, together with Physcomitrium minutulum Müll.Hal., c. 200 m, 05.IX.2003, Müller NC872 (DR).

COMMENTS

The genus Riccia L.is represented in New Caledonia by R. crinita Taylor and R. numeensis Steph., doubtful records exist for R. fluitans L. and R. junghuhniana Nees & Lindenb. (Thouvenot et al. 2011). Riccia crinita and R. numeensis both are belonging to sect. Riccia; the latter one is endemic to New Caledonia and was described by Stephani based on sterile material.

The specimen Müller NC872 belongs to subgenus Ricciella . The thallus cross-section shows regularly large air chambers (Fig. 3D, E). The capsules are bulging into spherical structures on the ventral surface. The inner thallus cells are thick-walled. The spores are about 60 µm in diameter and clearly reticulate on both faces with 7-8 alveolae across diameter on distal face and a small wing (Fig. 3 A-C).

Riccia hasskarliana is very similar to R. junghuhniana and R. multifida (Steph.) Steph. Riccia junghuhniana is a larger plant with branches 1.25-2.5 mm wide, with narrow airchambers (Meijer 1958) and the sporophytes are not as prominent on ventral surface. Riccia hasskarliana differs from the Australian R. multifida by spores with a less prominent wing and a lower number of alveolae across diameter on the distal face of the spores (6-8 vs 8-12) (Cargill et al. 2016).

Riccia hasskarliana was hitherto known from Indonesia (Java,

Kalimantan, Sumatra) (Meijer 1958) and India (Singh 2014).