Weissia controversa, OK, 1853

Ignatova, E. A., Fedorova, A. V., Kuznetsova, O. I. & Ignatov, M. S., 2024, Notes on the genus weissia in russia focused mainly on the species from asian russia, Arctoa 33 (1), pp. 50-60 : 53-55

Weissia controversa in the Russian Far East

This is the most widespread species of the genus, distributed nearly worldwide. In Russia, it is frequent in its European part, except its northern regions, known from the Caucasus, southern Siberia, and southern Far East in the Asian part of the country. Bardunov & Cherdantseva (1982) characterize it as a more or less common species in southern Primorje, often found with sporophytes. It was also recorded from Kamchatka, Amurskaya Province, Khabarovsk Territory, Sakhalin, and Kuril Islands ( Cherdantseva et al., 2018). Weissia controversa is recognized by combination of widely and tightly incurved margins in upper halves of leaves and peristomate capsules on long setae. Its peristome teeth are characterized as well developed, linear-lanceolate, papillose, or sometimes rudimentary (if W. wimmeriana ( Sendtn.) Bruch, Schimp. & W. Gümbel is treated as a variety of W. controversa ). Its spore size is described more or less uniformly in Floras of various regions: 16–20 µm ( Smith, 2004), 18–20 µm ( Guerra et al., 2006), 17–20 µm (Savicz-Lyubitskaya & Smirnova, 1970); 15–20 µm ( Saito, 1975), 14–22 µm ( Crum & Anderson, 1981). In the course of present study, three specimens from Sakhalin and Kuril Islands identified as W. controversa took our attention. The molecular phylogenetic analysis resolved them in a separate, highly supported clade. Weissia controversa , as well as most other widespread species of Weissia , was found to be polyphyletic by Werner et al. (2005) and in our analysis, based on sequences of ITS1–2 region. The main morphological characters of plants from Sakhalin and Kuril Islands, such as leaves with incurved upper margins and capsules on long setae with lanceolate, entire peristome teeth are in agreement with W. controversa ; however, some differences are also observed: their leaf margins are narrower incurved, and its spores are larger, (19–)21–25 µm. We consider that these differences, as well as a separate position in the molecular phylogenetic tree allow us to describe these plants as a variety of W. controversa .

Eperistomate Weissia in the Russian Far East

Weissia edentula has been first recorded in Russia from Bureinsky Nature Reserve in Khabarovsk Territory ( Ignatov et al., 2000). Later specimens of Weissia with long setae and eperistomate capsules were collected in other localities in the southern Russian Far East, from Zeya Reserve in Amurskaya Province to Primorsky Territory and Kuril Islands, the northernmost one in Kamchatka Peninsula; they were also identified as W. edentula . This species was described from Madras, India and is also known from China, Japan, Vietnam, Thailand, the Philippines, Papua New Guinea, Africa, and Australia ( Li et al., 2001; Brinda & Atwood, 2024). Its presence in SE Russia did not look impossible, likely representing populations on the northern boundary of its range. However, in the course of preparation the treatment of Weissia for the ongoing volume of the Moss Flora of Russia, we found that the plants from Russia called W. edentula do not fit comfortably the description of this species provided by Saito (1975) and Li et al. (2001) and especially its illustrations in Saito (2005) and Gao (1996). In these illustrations, leaves of W. edentula are shown as linear-lanceolate, narrowly acuminate, with more or less strongly involute upper margins, whereas plants from Russia have shorter and wider leaves, with lower length/width ratio, with much narrower and weaker incurved margins, and obtuse apices ( Fig. 4 ). In Japan, there are two other eperistomate species of Weissia , i.e. W. atrocaulis K. Saito and W. newcomeri (E.B. Bartram) K. Saito , both having oblong leaves with obtuse apices ( Saito, 1975; Noguchi & Iwatzuki, 1988). However, W. atrocaulis has totally plane leaf margins, percurrent costa, and longer capsules; furthermore, it is described as a robust plant with black stems to 3 cm long. The plants from the Russian Far East lack this combination of characters. Weissia atrocaulis is currently treated in Trichostomum where it was transferred by R.H. Zander. At the same time, the plants in question from the Russian Far East ( Fig. 4 ) are very similar to W. newcomeri , as it is illustrated and described by Saito (1975). They have oblong leaves with length/ width ratio 4–6:1, with slightly and narrowly incurved margins, obtuse apices, and shortly excurrent costa. All other morphological characters of plants from Russia fit well the description of this species. So we only with a little hesitation refer the plants from the Russian Far East not to W. edentula but to W. newcomeri , keeping in mind that it should be tested with molecular methods, if the specimens of W. newcomeri from Japan and W. edentula from East Asia will be available.

Figures

Fig. 4. Weissia newcomeri (from: Russia, Khabarovsk Territory, Bureinsky Nature Reserve, Bureya, Ignatov 97-1262, MHA). A–B: capsules; C: habit, dry; D: habit, wet; E: exothecium at urn mouth and spore; F–G: upper stem leaves; H: mid-leaf cells; I: upper leaf cells; J–K, M: lower stem leaves; L: leaf transverse section; N: basal leaf cells. Scale bars: 2 mm for A–D; 1 mm for F– G, J–K, M; 100 µm for E, H–I, L, N.