Enrothia Ignatov & Fedosov, 2019

Fedosov, V. E. & Ignatov, M. S., 2019, Enrothia, a new genus of Neckeraceae (Bryophyta) from East Asia, Arctoa 28 (1), pp. 12-17 : 13

Enrothia Ignatov & Fedosov , gen. nov.

Type: Enrothia polyclada (Müll. Hal.) Ignatov & Fedosov ( Neckera polyclada Müll. Hal. )

Etymology: In honour of Johannes Enroth (b. 1956), a bryologist from Helsinki, Finland, who with his colleagues has provided outstanding contributions to the Neckeraceae systematics.

Diagnosis: Combination of overall Neckeroid shoot architecture, erect-spreading leaves, attenuate and smallleaved at branch tips, the leaves at branch tips often caducous and immersed capsules differentiate the new genus from other genera.

Description: Medium-sized to robust plants, mostly on calcareous rocks. Primary stems creeping, very thin, with minute leaves. Secondary stems pinnately and moderately densely branched, the branches forming acute angles with the stem, densely subcomplanately foliate, branches partly with attenuate ends with minute leaves, these leaves often caducous; similar tiny shoots may also appear as reiterations on secondary stems; proximal branch leaves lanceolate and 1–2(–3) outermost somewhat distant from densely foliate, hemispheric branch primordium; axillary hairs conspicuous, numerous per leaf axil, of 4–6 cells, brown thoughout. Stem and large branch leaves ligulate, more or less broadly acute to apex, enlarging from basal parts of plant upwards, and accordingly with their size varying from hardly to distictly undulate, which is more expressed in large, better developed and fertile plants; margin serrulate to moderately serrate near apex, costa single, half-leaf up. Dioicous. Perichaetia narrow-tubulose. Seta short, capsule immersed.

Molecular phylogenetic analysis resolved Enrothia in the “ Pinnatella -clade”, far from Neckera s. str., the latter being also morphologically distinct in having a double, short or absent costa. A long single costa occurs in many Neckeraceae genera, e.g. Forsstroemia , Homalia , and Pinnatella , but the character state combination mentioned in diagnosis is not known to us in other Neckeraceae . Molecular phylogenetic results point most close relationship of Enrothia with Curvicladium kurzii (Kindb.) Enroth , Neckera himalayana Mitt. , and N. warburgii Broth. Among these, the former has a much stronger costa, reaching 0.9 leaf length, leaves distally coarsely serrate with multistratose teeth. Neckera himalayana is a large distinctly complanate plant with broadly ovate leaves, the leaf axis forming with the stem an angle close to 90°. Neckera warburgii is the only species of these three, with occasionally attenuate branch tips bearing smaller leaves, but this species has a longer costa and leaves strongly serrate near apex, and its capsules are exserted on setae many times longer than capsules. The species resembles Taiwanobryum (e.g., T. undulatifolium ; Ma et al., 2018), but it does not belong in that clade. Despite Neckera himalayana and N. warburgii remain in current classification in the “default” genus Neckera , their position in the “ Pinnatella -clade” obviously indicate a necessity of their placement in other, likely still undescribed genera (Olsson et al., 2016).