Seligeriaceae. Genus Seligeria

1. Urns cylindrical or ovate, length/width ratio >1. 5:1, not widened at the mouth, abruptly narrowed to setae; setae straight or arcuate; peristome present, teeth red, reflexed when mature and appressed to the capsule wall, rarely star-like spreading — 2
— Urns pyriform, cupulate, turbinate or hemispheric, length/width ratio 1:1, rarely slightly longer, widened or occasional not widened at mouth, gradually narrowed to setae; seta straight; peristome present, teeth orange to red, directed upward, star-like spreading or, rarely, reflexed; if urns are not widened at mouth, urns eperistomate — 5
2. Basal leaf cells mostly quadrate, rounded-quadrate, along costae in few rows short rectangular; leaf apices blunt, canaliculated to cucullate, two-layered — 2. S. subimmersa

Rare species with a scattered distribution. It grows on mineral soil covering cliff ledges, preferring calcareous rocks, occasionally with silicon dioxide, mostly near streams. It differs from S. diversifolia in predominantly subquadrate lower leaf cells and blunt, often cucullate, two-layered leaf apices.

— Basal leaf cells mostly short rectangular to elongate rectangular; leaf apices blunt, acute or acuminate, newer cucullate, one layered — 3
3. Stems 1-3(-6) µm long; perichaetial leaves often strongly enlargered, from strongly widened often tubulose base abruptly narrowed to short, blunt acumen; setae straight or arcuate; northern European Russia and Asian Russia — 3. S. diversifolia

A mainly Asian species growing mostly on calcareous sandstones, sandy limestones or igneous rocks, rich both in calcium and silicon. In some cases it is difficult to separate S. diversifolia from S. campylopoda, though molecular phylogenetic data confirm their distinction. Differences in the size and shape of their perichaetial leaves and mainly straight vs. distinctly arcuate setae are helpful for their recognition.

— Stems less than 0. 5 µm long; perichaetial leaves slightly longer than stem leaves, not tubulose at base, gradually narrowed into subulate acumina; setae arcuate; European Russia and southern Far East — 4
4. Costae excurrent, filling subulate leaf acumina; upper leaf cells mostly short-rectangular — 4. S. recurvata

Rare species known in Russia from the Caucasus, Karelia and Far East. It differs from S. cam­pylopoda in its excurrent costae and preference for substrates with a higher content of silicon.

— Costae percurrent, not filling leaf acumina; upper leaf cells mostly subquadrate — 5. S. campylopoda

This species is sporadic in lowland European Russia, growing in places where suitable calcareous rocks are present. For its distinction from S. diversifolia see comments under that species.

5(1). Urns semispherical or cupulate; peristome absent; spores small, 8-11 µm — 6. S. donniana

A rare species known from scattered localities throughout Russia. Its plants are the smallest in the genus, and often grow as small, scattered individuals. We include S. galinae, described as dioicous, in the autoicous S. donniana due to the occurrence of proterandry in this group. In addition, molecular data do not support the segregation of S. galinae from S. donniana

— Urns mostly turbinate or cupulate, never semispherical; peristome present or rudimentary; spo­res 8-32 mm, in species with cupulate capsules mostly larger than 14 µm — 6
6. Spores 8-13 µm — 7
— Spores 14-30(-32) µm — 9
7. Peristome teeth robust, nearly equal to urn mouth width, bright red; exothecial cells rectangular with moderately thickened walls, arranged in regular rows — 7. S. brevifolia

This species is known in Russia from a few localities in Karelia, Urals, Siberia and Kamchatka. Large and bright red peristome teeth, rather narrow capsules and small spores are important for its separation from S. tristichoides.

— Peristome teeth weaker, more when two times shorter than urn mouth width, whitish to orange; exothecial cells rounded-polygonal with strongly thickened walls, not arranged in regular rows — 8
8. Lower stem leaves lanceolate to linear-lanceolate, rather short subulate; perichaetial leaves remarkably larger than lower leaves, long subulate — 8. S. acutifolia

The species occurs in Russia only in NW Caucasus, where it has been found in Lagonaki Plateau on shaded limestone boulder. According to molecular data, the species is weakly delimited from S. pusilla. Morphologically it differs from this species in long subulate perichaetial leaves, which are remarkably larger than lower stem leaves, while in S. pusilla the proportion of vegetative vs perichaetial leaves is mostly opposite. According to our observation, the setae length is quite unstable character in Seligeria and it is not useful for species delimitation.

— Lower stem leaves linear, long subulate; perichaetial leaves no longer than lower leaves or even shorter due to shorter subulae — 9. S. pusilla

This species is rather widespread in European Russia and known from scattered localities in Siberia and Russian Far East. It is one of the most common species of the genus, growing on shaded limestone (usually on more or less pure one). Delicate long leaves with relatively thin costae are characteristic of this species.

9 (6). Setae mostly 1-1. 5 µm long; capsules cupulate; peristome teeth short stumped, often broken above after dehiscence; columellae weak, not or slightly protruding, opercula not systylious; spores 14-18 µm — 10. S. calcarea

This species is sporadic in the steppe zone of European Russia and grows on chalk outcrops. Its overall distribution in Russia is mostly southern; it is rare in boreal areas. Stiff leaves and rather short setae are characteristic for S. calcarea.

— Setae mostly longer than 1. 5 mm; capsules turbinate, occasionally cup-like; peristome teeth long triangular, red, glossy, mostly not broken after dehiscence, or, if peristome teeth short stumped, then opercula systylious on robust, long protruding columellae; spores (14-)18-28 (-32) µm — 10
10. Plants blackish; leaves not trifarious, concave; northern, mostly Arctic species — 11
— Plants green, olivaceous to brownish; leaves more or less trifarious, keeled; montane species, extending to the Arctic — 12
11. Central strand presents; alar cells more or less clearly differentiated; capsules sharply narrowed toward setae, often slightly contracted below mouth; columellae not protruding, opercula falling; peristome teeth long-triangular, star-like spreading to reflexed, red — 1. S. polaris

This species is sporadic in the Arctic and slightly extends southwards. In contrast to most other species of the genus, it grows on calcareous deposits along streams and creeks, mineral soil in tundra or near permanent snow beds rather than on rock faces. Its robust, blackish plants, strongly differentiated alar cells, star-like spreading peristome and large spores greatly help in recognizing the species.

— Central strand absent; alar cells not differentiated; capsules gradually narrowed toward setae, when mature strongly widened above; opercula systylious on robust, long protruding columellae; peristome teeth short stumped, pale orange — 11. S. oelandica

This species is known in Russia only in Chukotka and southern Taimyr where it is locally common on limestone rocks with high silicon dioxide content. It is similar to S. tristichoides, but differs in having blackish plants, non-trifarious leaves, shortly excurrent costae, very fragile peristome teeth (often broken shortly after dehiscence), systylious opercula and somewhat larger spores.

12. Leaves in distinct rows, linear; leaf apices subulate; costae shortly excurrent; spores 24-32 µm — - 12. S. trifaria

Seligeria trifaria is known in European Russia from a few highly scattered localities. It is distinct from other Seligeria species by its sharply trifarious leaf arrangement, linear leaves with subulate leaf tips and large spores.

— Leaves not in distinct rows, lanceolate to linear-lanceolate; leaf apices acute; costae subpercurrent to percurrent; spores (14-)18-24(-26) µm — 13. S. tristichoides

This species is scattered to locally common in boreal and subarctic zones of Siberia, mountains of South Siberia and also known from Dagestan in the Caucasus. It is characterized by large spores, funnel-shaped capsules and keeled leaves.