Pseudotaxiphyllum elegans (Brid.) Z.Iwats.

Osman, Imen Ben, Hugonnot, Vincent, Muller, Serge D. & Daoud-Bouattour, Amina, 2021, Four bryophytes collected in Tunisia, new for mainland Africa, Cryptogamie, Bryologie 20 (16), pp. 213-219 : 216

Pseudotaxiphyllum elegans (Brid.) Z.Iwats.

SPECIMENS EXAMINED. — Tunisia, Kroumiria, Jendouba Governorate, Delegation of Fernana: Oued Zen (36°48’43.08”N, 08°50’41.33”E; 368 m a.s.l.; site 2019-20), 04.IV.2019, leg. Imen Ben Osman, Vincent Hugonnot, TUN2019-282.

DISTRIBUTION. — Widespread in Europe, rare in the Mediterranean region ( Ros et al. 2013; Hodgetts & Lockhart 2020); Tristan da Cunha ( Ochyra & Plášek 2020); Asia (E Russia, Turkey; Afonina 2004; Cherniad”eva 2012; Ören et al. 2012); N and S America ( Hoe 1979; Ireland & Buck 2009; Ireland 2014).

Pseudotaxiphyllum elegans is also mentioned in “Afr 1” (which corresponds roughly to North Africa) by Wijk et al. (1964), but it is not cited either in the checklist of Northern Africa ( Ros et al. 1999) and the Mediterranean region ( Ros et al. 2013), nor in O’Shea (1995). Therefore, we consider this record as doubtful.

FLORISTIC ELEMENT. — Pan-Holarctic, having a strongly disjoined suboceanic boreo-temperate range in the Northern Hemisphere (bipolar species).

HABITAT

Transitional zone between alder riparian gallery and zeen oak forest on the higher banks of a permanent wadi and on soil between sandstone rocks. The forest canopy is composed of Alnus glutinosa (L.) Gaertn., Quercus canariensis and Ilex aquifolium L.

The habitat of Pseudotaxiphyllum elegans in Tunisia is similar to that in Europe (Blockeel et al. 2014). This species usually occurs in acid forest stands where it grows on soil around the bases of trees, on sheltered banks, and also commonly on and among rocks, both on raw humus and over bare surfaces. The alder swamps and riparian forests of Kroumiria are known to host a variety of vascular plants with Northern affinities, as previously emphasised byBraun-Blanquet (1953). The occurrence of several sterile bryophytes of Northern-Oceanic affinity in the Oued Zen Valley ( Heterocladium flaccidum (Schimp.) A.J.E.Sm., Isothecium myosuroides Brid. , Lophocolea fragrans (Moris & De Not.) Gottsche, Lindenb. & Nees , etc.) offers a strong argument for the ancient origin of these populations associated with sexual depletion ( Hugonnot et al. 2020).

REMARKS

At present, the Oued Zen Valley is legally protected (National Park of Oued Zen), but illegal cutting trees by local residents could threaten this site of high conservation value.

The Tunisian population of Pseudotaxiphyllum elegans was sterile. It was present only very locally over a few cm², the population consisting of several tenths of stems.

COMMENTS

The Tunisian specimens do not deviate significantly from European ones. They are typically small, with strongly Plagiothecium -like complanate leaves, have filamentous pseudoparaphyllia and caducous axillary branchlets ( Cano 2018).