Schistidium helveticum (Schkuhr) Deguchi

Osman, Imen Ben, Hugonnot, Vincent, Muller, Serge D. & Daoud-Bouattour, Amina, 2022, New bryophytes for Tunisia (North Africa). Part 2: other families, Cryptogamie, Bryologie 20 (11), pp. 173-185 : 180

Schistidium helveticum (Schkuhr) Deguchi

SPECIMENS EXAMINED. — Tunisia. Tunisian Dorsal, Ben Arous Governorate, Delegation of Mornag: Jbel Ressas, northwestern side, 36°36’14.39”N, 10°19’56.07”E, 610 m a.s.l. (site 2020-50), 15.III.2020, Ben Osman & Hugonnot (TUN[TUN2020-11]); Jbel Ressas, north side, with sporophytes, 36°36’15.46”N, 10°19’57.79”E, 620 m a.s.l. (site 2020-51), 15.III.2020, Ben Osman & Hugonnot (TUN[TUN2020-12]).

REMARKS

Schistidium helveticum was growing on calcareous rocks on the slopes and cliffs of the Jbel Ressas in a degraded woodland of arar trees ( Tetraclinis articulata (Vahl) Masters ).

In North Europe, this saxicolous moss grows on highly exposed calcareous rocks in warm sites (Blom 1996; Bosanquet 2014b). In southern regions, it also occurs in more shaded and humid localities, sometimes on north-facing slopes. The ecological situation of Tunisian populations is clearly representative of its general requirements in southern regions.

The species is characterized by its deep brown-blackish color with a golden sheen. The leaves are muticous or have a very short hyaline point in the perichaetial leaves. The lamina is partially bistratose and the cells are mostly isodiametric and slightly sinuose. The perichaetial leaves are enlarged, lanceolate, and do not conceal the entire capsule. The exothecial cells are mostly oblong. The peristome is well developed with long semi-perforate teeth.

Schistidium helveticum is a European southern-temperate species. It occurs commonly in Mediterranean Europe but is restricted to the lowlands in central Europe and seems to be absent from Eastern Europe (Blom 1996; Hodgetts & Lockhart 2020). It also occurs in North Africa ( Ros et al. 2013) and Southwestern Asia ( Kürschner & Frey 2020).