Schistidium marginale H.H.Blom, Bednarek-Ochyra & Ochyra, 2016

Blom, Hans H., Bednarek-Ochyra, Halina & Ochyra, Ryszard, 2016, Studies on Schistidium (Grimmiaceae, Bryophyta) in Europe, with particular reference to the Alps: I. A description of S. marginale sp. nov., Phytotaxa 247 (3), pp. 210-218 : 211-216

Schistidium marginale H.H.Blom, Bednarek-Ochyra & Ochyra , sp. nov., Figs 1–2

Nostra species nova Schistidio conferto et S. echinato similis, sed ab illa costis grossissimis crassissimisque, in sectione transversali superne et medio 3–4-stratosibus, basi 4-stratosibus et pilo hyalino rigidiori crassiorique distincta est; prior species a nostra capsulis ovoidis, obovoidis vel breviter obloidis, deinde frequenter cyathiformibus campanulatibusque, 0.9–1.4(–1.7) longiori quam latiori, altera margine recurvo versus apice et dentibus pili longioribus plus protrudentibus bene distinguitur.

Type: AUSTRIA. Steiermark, Gurktaler Alpen, Frauenalpe mountain south of Murau, alt. ca 1900 m a.s.l., [lat. ca 47º03′23″N, long. ca 14º08′18″E], on S-facing, base-rich schistose rock, 28 June 1996, Köckinger 96-437 (holotype: TRH!, isotype: KRAM!).

Plants small, dull, olivaceous or brownish above, often with yellowish tones, brownish below, turning pale yellowish in old herbarium material, forming dense, sometimes extensive tufts or mats. Stem 0.9–2.5 cm, slender, irregularly branched, in transverse section with 2–3-stratose epidermis of cells with relatively large lumina and thin-walled medullary cells, with narrow central strand, consisting of about 10–15 or more cells. Axillary hairs filiform, hyaline throughout, uniseriate, 4–7-celled, with 1–4 short, quadrate basal cells and 3–4 elongate distal cells. Leaves densely set, shiny, erect, imbricate, straight, narrowly ovate-triangular, acute or rarely acuminate, keeled, 1.5–2.1 × 0.4–0.6 mm. Hair-point 0–0.7(–0.85) mm, straight and rather stiff, ± flattened in lower part, not decurrent, coarsely spinulose with short, erect to erecto-patent spinulae, dorsally densely spinulose. Costa smooth, robust, in upper and central parts 48–75 μm wide, about ⅓ leaf width in the narrow upper part of leaf, percurrent to shortly excurrent, dorsally high and ridge-like and making an acute angle with the lamina in transverse section, 2–3(–4) stratose in upper and central parts, trapezoid, subrectangular or irregularly angular in outline (sometimes forming a shallow furrow along the dorsal side), 3–4-stratose in lower part and subrectangular to hemispherical in outline. Margins smooth, mostly plane or very narrowly recurved for various lengths in the central part on one side and narrowly recurved in lower ⅓–⅔ or rarely almost throughout on the opposite side, often recurved almost to apex on one or both sides in larger subperichaetial leaves, in upper and central parts from bistratose for (1–)2–5 rows to 4-stratose, often subtriangular to clavate in outline, in lower part mostly bistratose for 1 row. Lamina smooth, in upper and central parts varying from unistratose with a few bistratose spots and strips to irregularly bistratose, in lower part unistratose. Laminal cells thick-walled, in upper part mostly isodiametric, rounded, ovate and elliptical mixed with a few oblong cells, esinuose, in central and lower parts predominantly shortly oblong, weakly to distinctly sinuose, 8–10 μm wide and up to 11–20 μm long; basal cells in a small juxtacostal group, (8–)10–12 μm wide and up to 22–33(–50) μm long; basal marginal cells quadrate or short rectangular, often subhyaline, with thickened transverse walls in 3–6(–7) rows. Perichaetial leaves ovate-elliptical, 2.1–3.0 × 0.7–1.0 mm, with margins broadly recurved in upper ⅓–⅔ of leaf and hair-points 0–0.7 mm. Calyptra small and narrow, fugacious, smooth, brownish, not extending to the margin of the urn rim, cucullate when young and becoming nearly mitriform with age (few studied).

Monoicous. Sporophytes almost always present, abundant, immersed. Seta pale yellowish, 0.1–0.3 mm. Urn greyish-brown to yellow-brown, ± shiny, obloid-cylindrical, becoming finely striate with age, 0.8–1.0 × 0.4–0.65 mm, with length/width ratio 1.6–1.9. Exothecial cells in upper part irregular, varying from quadrate to transversely elongate and mixed with oblong cells, in lower part predominantly oblong with slightly thickened walls, up to 20–30 μm wide and 55–65 μm long. Stomata large, surrounded by small differentiated thick-walled cells, 4–6 per urn. Peristome teeth 240–380 μm, orange-brown or dark reddish, straight, erect to erecto-patent but becoming squarrose with age, tapering to a fine, acute or obtuse point, varying from entire to much perforated with narrow slits along the median line, sometimes with split off prongs at upper margins, smooth in basal part, finely or rather coarsely and densely papillose above with narrow, short or rather long papillae in horizontal to oblique rows in central part. Columella long and narrow permanently attached to the conic-convex operculum with erect or oblique, straight rostrum, 0.15–0.3(–0.4) mm. Spores 8–10 μm in diameter, almost smooth.

Ecology and distribution: — Schistidium marginale grows on inclined, mostly south-facing rock ledges. It has been collected on acidophilous rocks such as granite and gneiss, but most frequently it grows on various types of hard schist. The species is known from the Alps of Austria and Switzerland, the Jura Mountains and Pyrenees, as well as from Macedonia, Turkey and the Caucasus (see list of cited specimens) ( Fig. 3 ). Its distribution in Carinthia, Austria, was mapped by Köckinger et al. (2008: 231). The elevation range of S. marginale extends from 1100 to 2350 m.

Etymology: —The specific epithet refers to the distinctly bordered leaf margins with very strongly thickened limbidia.

Relationship and differentiation: —Based on molecular studies of the rDNA ITS region, Schistidum marginale appears as a sister group to a clade comprising S. confertum and S. echinatum ( Ignatova et al. 2010: Figs 1–2 ). These two species are also thought to be the closest relatives of S. marginale based on morphological characters, and they are the most likely to be confused with it. These three species constitute a group of closely related species which may prove difficult to key out due to an overlap in quantitative characters. They are small mosses that share several important characters, including (a) short peristome teeth which are often much perforated, (b) a dorsally prominent, ridge-like costa, (c) small leaf cells which are esinuose or slightly sinuose in the upper and central parts of leaf, (d) a partly bistratose upper leaf lamina, (e) markedly thickened leaf margins, (f) basal leaf marginal cells with thickened transverse walls, (g) a flattened, distinctly dentate to spinulose hair-point, (h) leaf KOH + yellow reaction. All these traits are diagnostic for Schistidium sect. Conferta ( Vilhelm 1922: 53) Ochyra (in Ochyra et al. 2003b: 132) which was defined as the Confertum group within Schistidium ( Blom 1996) . Species of this section are widely distributed in mountainous areas in the Northern and Southern Hemispheres growing commonly on acidophilous rocks.

Plants of Schistidium marginale are slightly larger than those of the other two species. They possess longer leaves, 1.5–2.1 mm versus 1.0– 1.8 mm in S. confertum and 0.8–1.8 in S. echinatum . In addition, this species has the coarsest and thickest costa in this complex which is 3–4-stratose in central and usually 4-stratose in lower part of leaf, whilst it is 2–3-stratose and 3-stratose, respectively, in the other species. The angled costa which in some specimens forms a shallow but distinct furrow along the dorsal side in upper part of the leaf, is a unique feature, not seen in any known Schistidium species. Likewise, the leaf margins of S. marginale are also the most heavily thickened in the group.

In Schistidium marginale the leaf hair-point is thicker and stiffer than in the other species. Its structure is more similar to that of S. echinatum than S. confertum (see Ignatova et. al. 2010: Fig. 15) but the lateral and dorsal spinulae are distinctly shorter and less protruding in S. marginale and the hair-point of this species may appear quite smooth when inspected with the naked eye. The leaf margin of the vegetative leaves provides a further character distinguishing it from S. echinatum . In that species the margins are recurved towards the leaf apex on both sides of the leaf ( Ignatova et al. 2010: Fig. 14), whereas they are plane or narrowly and mostly shortly recurved on one side only in S. marginale ( Figs 1.17 –23). The obloid-cylindrical urn of S. marginale is similar to that in S. echinatum and they share similar length/width ratios— 1.5–1.8 in S. echinatum and 1.6–1.9 in S. marginale . However, the urn shape in these species differs markedly from the ovoid, obovoid to shortly obloid urn in S. confertum , which becomes cyathiform to campanulate with age and has length/width ratio 0.9–1.4(–1.7).

Additional specimens studied (paratypes): — AUSTRIA. Kärnten. Hohe Tauern, Säuleck mountain east of Mallnitz , Seealm , Köckinger 95-385 ( GZU). Kreuzeck massif, north of Oberdrauberg , Zwickenberger Ochsenalm , Köckinger 12343 ( KL, TRH) ; Nockberge, Falkert mountain, Köckinger 99-1233 ( KL) ; Karnische Alpen, Rattendorfer Alm west of Nassfeld Pass, Köckinger 12240 ( KL, KRAM) ; Karnische Alpen, Weidenkopf mountain north-west of Hochweisssteinhaus, 2200 m, Köckinger 12239 ( KL, KRAM) ; Karnische Alpen, Runseck mountain, Köckinger 12342 ( KL) ; Lange Alm south-west of Murau, cirque above Hirschtaler Alm, Köckinger 12344 ( KL) ; Gurktaler Alpen, Zgarten-Alm east of Turracher Höhe, Köckinger 96-523 ( GZU) ; Gurktaler Alpen, Nockberge, north-east side of Klomnock above Windeben, 1920 m, Köckinger 94-844 ( GZU, TRH). Steiermark. Seetaler Alpen, Lindertal north-east of Zirbitzkogel, Köckinger 95-321 ( GZU, TRH) ; Seetaler Alpen, above Wildsee, Köckinger 94-1607 ( GZU) ; Seetaler Alpen, Zirbitzen near Obdach, August 1887, Glowacki s.n. ( GJO) ; Triebener Tauern, Gr. Schober mountain, near Schoberpass, Köckinger 97-350 ( GZU, with S. confertum ) ; Gurktaler Alpen, Frauenalpe mountain south of Murau, Köckinger 96-433, 96-436, 96-438 & 96-439 ( BCB, GZU, NY, Z). Vorarlberg. Silvretta Mountains , southeast of Gargellen , 1950–2000 m, Köckinger 14889 ( KRAM, TRH). Tirol. Hohe Tauern, Windischmatrei, Messe (r)ling mountain, 21 August 1873, Gander s.n. ( S) ; Ochsental-Obertal, above Kühtai towards Finstertaler Seen, 19 August 1967, Düll s.n. (priv. herb., with Bucklandiella macounii subsp. alpina ) .

GEORGIA. Svaneti. Mamisson in the spring area of the Tskhenis-Tsquali river, 15 July1877, Brotherus s.n. (HBrotherus); Racha, Baraleti mountain near Uzeri, 3 July 1877, Brotherus s.n. (H-Brotherus).

ITALY. Trentino-Alto Adige. Adamello Mountains, Val de Genova, towards Mandronenhütte, 12 September 1903, Baumgartner s.n. ( W) ; below Laresgletcher towards Val de Genova, 20 September 1903, Baumgartner s.n. ( W) . Friuli-Venezia Gulia. Alpi Carnici, Rudenspitze mountain north of Forni Avoltri , Köckinger 12341 ( GZU) .

MACEDONIA. Bitola. Kaymakchalan (Voras) mountain above Kali Pediada, 1745 m, Erzberger 14053 (BErzberger, KRAM, TRH); Pelister Mountains, from hotel Molika through Kopanki tourist house to the spring of Magarevska stream (Česma), 1625–1745 m, Erzberger 124161, 14172 & 14178 (B-Erzberger, KRAM, TRH).

SPAIN. Huesca. Panticosa, Ordicuso, 24 August 1995, Heras & Infante s.n. (VIT, TRH).

SWITZERLAND. Vaud. Chasseron, Lesquereux s.n. ( NEU) ; Yvorne (?, illegible) 17 August 1840 Lesquereux s.n. ( NEU) . Bern. Sustenpass, 11 September 1905, Culmann s.n. ( Z) ; Bachalp above Grindelwald, 8 August 1905, Culmann s.n. ( Z) ; Andermatt , 19 July 1956, Casas s.n. ( BCB) . Uri. Sidelhorn, Grimsel, August 1891, Culmann s.n. ( Z) ; Göschener Tal, Blom 6082, 6085, 6110 ( TRH) . Valais. Champex, 8 April 1961, Albrecht s.n. ( Z) ; Ravoire, 8 April 1960, 9 April 1969, Albrecht s.n. ( Z) . Graubünden. Arosa, 3 August 1960, Albrecht s.n. ( Z) .

TURKEY. Artvin. Otingol, Stainton & Henderson 5995C (E).

Figures

FIGURE 1. Schistidium marginale. 1. Habit, wet. 2. Transverse section of stem. 3−6. Axillary hairs. 7−12. Vegetative leaves. 13−26. Transverse sections of leaves, sequentially from base to apex.(1−2, 7−10, 13−23 from Köckinger 96-437, isotype; 3−6, 11−12, 24−26 from Köckinger 12239, paratype; both in KRAM.) Scale bars: a − 1 mm (1); b − 100 μm (3−6, 13−26); c − 100 μm (2); d − 1 mm (7−12).

FIGURE 2. Schistidium marginale. 1−3. Leaf apices with hair-points. 4. Mid-leaf cells. 5. Basal cells. 6−7. Portions of branches with perichaetia, wet. 8−9. Perichaetial leaves. 10−11. Operculate capsules, wet. 12−13. Deoperculate capsules, wet. 14. Calyptra. 15. Operculum with attached columella. 16. Exothecial cells and stomata at base of urn. 17. Exothecial cells in middle of urn. 18. Exothecial cells at mouth, peristome and spores. (1−7, 10−14 from Köckinger 96-437, isotype; 8−9, 15−18 from Köckinger 12239, paratype; both in KRAM.) Scale bars: a − 1 mm (6−7, 10−14); b − 1 mm (15) and 100 μm (16−18); c − 100 μm (2−3); d − 1 mm (1, 4−5, 8−9).

FIGURE 3. Distribution map for Schistidium marginale.