taxonID	type	description	language	source
03FADB22FFC99D1030A2FE4FFB62FD83.taxon	description	In the analysis by Jiménez et al. (2022), one specimen from China, Xinjiang appeared in a clade with European specimens of D. validus; it hinted on the possible wider distribution of this species in Asia, but its morphological circumscription needed to be clarified. For the present analysis, 19 specimens identified as D. cf. validus or D. icmadophilus were sampled; they were resolved in a moderately supported (PP 1, BS 79) clade together with all available GenBank accessions of D. validus. This clade appeared in a sister position to D. wisselii & D. schensianus clade. A selection of specimens in a D. validus - clade represents plants from a wide geographical range: Central European Russia, Caucasus, Urals, Altai Mts in southern Siberia, different regions of Yakutia, Amur Province, Khabarovsk and Primorsky Territory in the south of Russian Far East. In their main morphological characters, they do not contradict the description and illustrations of D. validus provided by Jiménez (2000). Leaves and transverse sections of the sequenced specimens of D. validus are shown in Fig. 3. Most of these specimens have leaves with scarcely differentiated bases, without shoulders, gradually tapered into narrow acumina, having weakly recurved margins and shortly excurrent costae. Specimens from European Russia, including Urals and Caucasus, and one sample from central Yakutia have shorter (1.4 – 1.9 mm long) leaves than most oth- er specimens from Asian Russia (2.2 – 2.9 mm long). However, all these measurements are within the range of variability of this species given by Jiménez (2000): (1.2 –) 1.6 – 2.7 (– 3.2) mm. Thus, the presence and wide distribution of D. validus in Russia is confirmed. Noteworthy, according to Jiménez (2006), sexual condition and sporophytes are unknown in D. validus. Most of our sequenced specimens were also sterile, and only in two specimens, OK 3464 from Yakutia (Ust-Nera) and OK 4063 from Altai (Chemal) sporophytes were found. However, we failed to find any male inflorescences in these or other specimens. Sporophytic characters of D. validus are described in the Taxonomy section. Jiménez (2000) also mentioned that round multicellular gemmae are often present in leaf axils in D. validus; in our sequenced specimens gemmae were very rare.	en	Ignatova, E. A., Fedosov, V. E., Kuznetsova, O. I., Fedorova, A. V., Ignatov, M. S. (2024): On the genus Didymodon s. str. (Pottiaceae, Bryophyta) in Russia. Arctoa 33 (2): 129-155, DOI: 10.15298/arctoa.33.14, URL: https://doi.org/10.15298/arctoa.33.14
03FADB22FFC69D1F30FCFE2FFAA0FAD7.taxon	description	A potentially undescribed species revealed in the present analysis (see also discussion on D. acutus above) (1) Two specimens from Primorsky Territory (isolates OK 3317 and OK 4019) formed a maximally supported clade sister to one GenBank accession called D. icmadophilus from China, Heilongjiang (PP 0.94; BS 97). Their mutual clade was resolved as sister to D. wisselii clade without support, within clade 5. In some characters (excurrent costae, papillose leaf cells) plants from Primorsky Territory actually resembled D. icmadophilus, but they had leaves different in shape, widely spreading but not erect-patent when wet, and papillae on laminal cells small, sparse, present on both leaf surfaces. Their relationship to European D. icmadophilus was also not confirmed by molecular data, as the latter species was resolved in the clade 4 in our study, far from the specimens in question. These plants are described in the Taxonomy section under the name D. cherdantsevae. (2) Four specimens (isolates OK 3477, OK 3484, OK 4053, and OK 4101) from distant localities (Primorsky Territory, Yakutia, Dagestan) formed a maximally supported clade within clade 5, without obvious relationship with other species. They were uniform morphologically and resembled D. cordatus in having leaves with highly recurved margins, similar costa structure, papillose laminal cells and presence of multicellular axillary gemmae; however, they had different leaf shape, with scarcely differentiated bases, and their leaf margins were only slightly recurved but not revolute. These differences together with an evidence from molecular markers suggested that this is an undescribed species; it is described in the Taxonomy section as D. calciphilus. (3) Nine specimens from southern Siberia (Irkutsk Province, Buryatia, Zabaikialsky Territory, Khakassia, and Altai Republic, isolates OK 3321, OK 3455, OK 3457, OK 3474, OK 3475, OK 3489, OK 3496, OK 3519, and OK 4103 formed a maximally supported clade sister to D. mongolicus - clade within clade 5. They are characterized by having deltoid leaves with margins revolute almost to apices, papillose laminal cells, costae in transverse section with 2 – 3 layers of guide cells and no ventral stereids, and multicellular axillary gemmae occasionally present. This combination of characters partially resembled D. cordatus, D. tectorum and D. desertorum, but did not exactly fit any of these species. This fact, together with data from ITS, convinced us that this is a new species. It is described in the Taxonomy section as D. baicalensis. (4) Three specimens (isolates 3449, 3454 and 4108) from the Caucasus, Tyva and Yakutia were resolved within clade 4 in a highly supported (PP 1, BS 0.99) clade sister to D. hengduanensis, with low support for their mutual clade (PP 0.72, BS 57). These specimens are characterized by leaves tightly appressed when dry, straight, ovate-triangular, with long excurrent costae, fragile apices and unistratose laminae. This character combination is unique in Didymodon s. str.; thus these plants are described as a new species, D. abramovae in the Taxonomy section. Another three specimens with the same morphological characters (isolates OK 3451, OK 3452 and OK 4112) from Perm Territory, Ingushetia and Tyva were found in a grade at the base of fully supported D. borealis - clade. We tentatively refer them to D. cf. abramovae. (5) One morphologically very peculiar specimen from Altai Republic (isolate OK 3893) was resolved in an orphaned position. Despite only one such specimen was found, it is so distinct in morphology, that we decided to describe it in order to attract attention to it and make search of similar plants easier. It is described in the Taxonomy section as D. truncatus. Species that could be expected in the territory of	en	Ignatova, E. A., Fedosov, V. E., Kuznetsova, O. I., Fedorova, A. V., Ignatov, M. S. (2024): On the genus Didymodon s. str. (Pottiaceae, Bryophyta) in Russia. Arctoa 33 (2): 129-155, DOI: 10.15298/arctoa.33.14, URL: https://doi.org/10.15298/arctoa.33.14
03FADB22FFC69D1F30FCFE2FFAA0FAD7.taxon	materials_examined	Russia but not found in the present analysis	en	Ignatova, E. A., Fedosov, V. E., Kuznetsova, O. I., Fedorova, A. V., Ignatov, M. S. (2024): On the genus Didymodon s. str. (Pottiaceae, Bryophyta) in Russia. Arctoa 33 (2): 129-155, DOI: 10.15298/arctoa.33.14, URL: https://doi.org/10.15298/arctoa.33.14
