Jungermannia calcicola Konstant. et Vilnet, 2016

Konstantinova, Nadezda A. & Vilnet, Anna A., 2016, A new species of the genus Jungermannia (Jungermanniales, Marchantiophyta) from the Caucasus with notes on taxa delimitation and taxonomy of Jungermannia s. str., Phytotaxa 255 (3), pp. 227-239 : 234-236

Jungermannia calcicola Konstant. et Vilnet , sp. nova. Fig.3 .

The species is characterized by a combination of wide leaves and relatively collenchymatosus cells that are characteristic for Solenostoma s. str. with absence of perigynium and non beaked perianth that are diagnostic for Jungermannia . Other differentiating features are imbricate, distinctly concave to cap-shaped leaves and 3-spiral elaters.

Type:— Russia, Caucasus: Republic of Adygeia, left bank of Kurdzhips River, 44°04’59” N – 39°59’59” E, 1495 m elev., in crevices on wet cliff, on limestone rock with admixture of single plants of Mesoptychia badensis (Gottsche ex Rabenh.) L.Söderstr. et Váňa, (2012: 52) , Mesoptychia collaris (Nees) L.Söderstr. et Váňa, 2012: 53 , 11 October 2007, N. A. Konstantinova & A. N. Savchenko # K 429-1-07 (holotype KPABG). GenBank # JF 421608 (trn L –trn F cpDNA), KR 063630 (trn G intron cpDNA).

Plants 0.3–1 (1.2 just below perianth) mm wide and 4–8 (–10) mm long, grass-green—to fuscous green, not branched or sparsely branched, often with single subfloral innovation, branches both terminal and intercalary. Stolons rare in nearest part of shoot. Rhizoids numerous up to the apex of shoot, light brown, (7–)8–10 μm wide, very long, many times longer than wide of shoot up to 1.3 mm. Stem in cross section rounded, 140–170 μm, cells in the middle isodiametric, thin walled with minute trigones, (15–)17–19 μm. Cells of dorsal side of stem distinctly elongated, 22–25 × 31–40(–48) μm. Leaves very obliquely inserted, imbricate, distinctly concave to cap shaped, suborbicular, on sterile shoots mostly wider than long (350)380–450(500–530) μm wide and (270–)300–360(–460) μm long, near gametangia slightly larger 500–530 wide × 370–450 μm long. Cells thin walled with distinct trigones, marginal cells 15–17 μm, in the middle (15–)17–20 × 19–25(–28) μm, cuticle coarsely striate-papillose. Oil bodies 2–3(–4) per cell, dark grey, large, from almost spherical 6–8(–10) μm to widely elliptical 8–9 × 10–12(–14) μm. Dioicous. Bracts lager than leaves 690–740 μm wide and 550 μm long. Perianth terminal, distinctly pluriplicate exerted from bracts for 0.5 of its length, obovoid, not beaked, with more or less rounded apex, mouth with one-celled cilia-like teeth that are (11–)12–15(–16) × (26–)45–54 μm, cells below mouth more or less isodiametric, 15–18(–21) × 19–20(–23) μm, perigynium absent. Perianth and immature sporophytes were present in most collected specimens, but mature sporophytes were only found in a specimen collected by G. Doroshina on Scalistyi Ridge ( G 114388), so the description of capsules, spore and elaters is based on this specimen. Capsules dark brown, spherical, epidermal cells with nodular thickenings. Elaters (7–) 8–9 μm wide, 3-spiral with band to 2 μm wide; spores 12–16 μm, reddish-brown ( Fig. 3 ).

Ecology:—The species is restricted to strictly calcareous (limestone) substrates. It occurs at relatively high elevation (1450–2090 m) mostly in crevices of rocks, between and under rocks or in grottos where air humidity is relatively high. The species usually grows creeping on rock in thin mats. Associated species are Mesoptychia spp. and Conocephalum spp.

Distribution: —So far the species is known from the Caucasus, particularly from the republics of Adygeia, Karachaevo-Cherkessia and Dagestan ( Fig. 1 ).

Additional specimens (paratypes) studied:— Republic of Karachaevo-Cherkessia: Scalistyi Ridge, Gumbashi Mount , 43°46’18” N – 42°13’15” E, alt. 2065 m, N. A. Konstantinova & A. N. Savchenko #K-402-8-10 ( KPABG; GenBank accessions ## KR063595 , KR063631 ) ; Bermamyt Mountain , 43°41’21” N – 42°27’47” E, alt. 2443 m, 13 July 2010, G. Doroshina, # G114388 ( KPABG) ; eastern Caucasus, Republic of Dagestan, Gunib Plateau northwestfacing rock outcrops, 42°24’01” N – 46°54’ 09” E, alt. 2090 m, N. A. Konstantinova, # К60-9 - 11 ( KPABG; GenBank accessions ## KR063596 , KR063632 ) .

Differentiation: —The species can be confused with Jungermannia atrovirens from which it differs in 1) the generally smaller size, the width of plants without perianth usually not exceeding 0.3–0.5 mm; 2) the shape of the leaves that are wider than long with wide/length ratio (1.2–)1.3–1.5, with the most wider part near the middle whereas in J. atrovirens the leaves are usually longer than wide or slightly wider and more or less cordate; 3) the bracts appressed not spreading vs. spreading or erect-spreading in J. atrovirens ; 4) distinct and usually relatively large trigones especially in perianth cells; and 5) 3-spiral elaters whereas in J. atrovirens they are 1–2 spiral.

Etymology:—The epithet indicates that this species is found on calcareous substrates.

KEY FOR THE SPECIES OF JUNGERMANNIA S. STR. OCCURING IN RUSSIA

1. Paroicous (rare heteroicous), mostly fertile, usually small, not exceed 1.2 mm (1.5) wide..............................................................2

- Dioicous..............................................................................................................................................................................................4

2. Plants prostrate, creeping, leaves distant, flattened, rarely slightly concave, broadly ovoid, very obliquly inserted, plants occurring on Ca-rich substrates, known only from the type locality in the Far East of Russia................................................ J. konstantinovae

- Leaves usually approximate to imbricate, more rarely distant, but then leaves are concave, scale like and wide of stem is 0.25–0.4 wide of shoot, plants apart some arctic forms semi-erect..................................................................................................................3

3. Leaves longer than wide, width of stem do not exceed 0.2–0.25 wide of shoot............................................ J. pumila subsp. pumila

- Leaves as wide as long, usually concave or caniculate, wide of stem is 0.25–0.4 wide of shoot ................. J. pumila subsp. polaris

4. Plants large, (1.5) 2–4 (6) mm wide, usually dark green, leaves narrow inserted, broadly triangular and cordate at base, sheathing the stem, often with dark red or reddish brown cell walls, perianth mouth crenulate, cells below mouth generally elongate............ ...................................................................................................................................................................................... J. eucordifolia

- Plants usually less than 2 mm wide, leaves not or slightly sheathing the stem and not or slightly cordate at base...........................5

5. Plants very small, width of shoot without perianth not exceed 0.5–1 mm, leaves imbricate, distinctly concave to cap shaped, suborbicular, on sterile shoots mostly wider than long, widest in lower third of leaf, wide/length ratio (1.2–)1.3–1.5, cells with distinct and relatively large trigones, elaters 3-spiral..................................................................................................................... J. calcicola

- Plants usually more than 0.7 mm wide, leaves flattened, slightly concave or cucullate near apex but never cap shaped, as wide as long or longer than wide, elaters 2 spiral...........................................................................................................................................6

6. Plants dull green to yellowish-brown and brown, leaves flat or concave, androecia consist of 6–10 pairs of bracts, species restricted to Ca-rich substrates ......................................................................................................................................................... J. atrovirens

- Plants dark green to blackish and black-brown, leaves slightly concave, androecia consist of 3–4 pair of bracts, species restricted to acidic or neutral substrates.............................................................................................................................................................7

7. Plants small with shoots 0.7–1.2 (1.3) mm wide, leaves distinctly cucullate at apex, laterally appressed to the stem ...... J. borealis

- Plants (1) 1.2–2.5 mm wide, leaves usually flat or slightly concave, spreading, cells of leave walls often rusty-red or brown .......... ........................................................................................................................................................................................ J. exsertifolia

Figures

FIGURE 1. The map of distribution of Jungermannia calcicola Konstant. et Vilnet. 1—Kurdzhips River (Republic of Adygeia, type locality); 2—Scalistyi Ridge, Gumbashi Mount (Republic of Karachaevo-Cherkessia); 3—Scalistyi Ridge, Bermamyt Mountain (Republic of Karachaevo-Cherkessia) and 4—Gunib Plateau Dagestan Republic).

FIGURE 3. Jungermannia calcicola Konstant. et Vilnet. 1—Plants of Jungermannia calcicola; 2—leaves on sterile shoot; 3—bracts; 4—perianth mouth; 5—cells of the middle of leaf with oil-bodies; 6—cells of perianth; 6—elaters; 7–8—cells of capsule wall.