Hygroamblystegium varium (Hedw.) Mönk. var. varium

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 : 175-176

Hygroamblystegium varium (Hedw.) Mönk. var. varium

SPECIMENS EXAMINED. — Tunisia. Kroumiria, Jendouba Governorate, Delegation of Aïn Draham: Dar Fatma, with sporophytes, 36°49’06.92”N, 08°46’29.70”E, 783 m a.s.l. (site 2019-36), 05.IV.2019, Ben Osman & Hugonnot (TUN[TUN2019-278]); 36°49’08.15”N, 08°46’28.80”E, 782 m a.s.l. (site 2019-37), 05.IV.2019, Ben Osman & Hugonnot (TUN[TUN2019-279]); Mogods, Bizerte Governorate, Delegation of Sejenane:Cap Serrat, with sporophytes, 37°12’17.00”N, 09°13’50.60”E, 3 m a.s.l. (site 2019- 65), 08.IV.2019, Ben Osman & Hugonnot (TUN[TUN2019-294]).

REMARKS

Hygroamblystegium varium var. varium was found in two contrasting habitats: on floating peat in the Dar Fatma peatland, covered by rich herbaceous carpets dominated by Baldellia repens (Lam.) van Ooststr. ex Lawalrée , Lotus pedunculatus Cav. , Lysimachia tenella L., L. tyrrhenia (Thore) U.Manns & Anderb. and Potamogeton polygonifolius Pourr. , and on soil in the riparian alder forest of Oued Ziatine on Cap Serrat.

The Dar Fatma peatland is unique in North Africa and designated as a Natural Reserve in 1993. Its raised circular mounds of waterlogged peat measuring 15-25 m ² are separated by wet lawns and surrounded by hygrophilic scrublands of Erica scoparia L. and Pteridium aquilinum (L.) Kuhn ( Muller et al. 2010). Hygroamblystegium varium var. varium was accompanied by a remarkable hygrophilous assemblage of species, including Aulacomnium palustre (Hedw.) Schwägr , Philonotis fontana (Hedw.) Brid. , Plagiomnium affine (Bland. ex Funck) T.J.Kop. , Riccardia multifida (L.) Gray and Sphagnum auriculatum Schimp. , which are all rare bryophyte species in North Africa.

The taxonomic treatment of the Hygroamblystegium varium complex has changed substantially in recent years ( Vanderpoorten 2004). The Tunisian material is particularly difficult to identify because it combines characteristics of var. humile (P.Beauv.) Vanderp. & Hedenäs and var. varium . However, it is attributed to var. varium because typical morphotypes occur in all the localities. The deviant morphs are considered juvenile or underdeveloped specimens.

Hygroamblystegium varium var. varium is characterized by its shortly acuminate or obtuse leaves, the nerve nearly reaching the apex, and the short rhomboidal cells.

Hygroamblystegium varium var. varium is a circumpolar temperate taxon present everywhere on the American continent as well as in Eurasia, South Africa, New Zealand and Antarctica ( Vanderpoorten 2014).