Frullania dorsimamillosa Mamontov, Hentschel, Sofronova et Potemkin, 2015

Potemkin, Alexey D., Hentschel, Jörn, Sofronova, Elena V. & Mamontov, Yuriy S., 2015, Frullania dorsimamillosa, a unique new species from Central China and the resurrection of Frullania chinlingensis (Frullaniaceae, Marchantiophyta), Phytotaxa 227 (1), pp. 1-12 : 5-8

Frullania dorsimamillosa Mamontov, Hentschel, Sofronova et Potemkin sp. nov. Figs 1–4 .

Type: — China, NE Sichuan, Minshan Range, Songpan County, valley of R. Fujiang 3 km E of Huanglong hotel, Picea - Salix -Juniperus rich fen, lower oroboreal zone, collecting locality 5c, on a trunk, 32°45’N 103°52’E, 2900 m, 15.09.1991, T. Koponen 45098, c.per. (holotype: H; isotypes JE, LE) .

Diagnosis: —Greenish brown to purplish brown plants with unipapillose-mammillose dorsal surface of lobes. The species is furthermore characterized by its concave female bracts which adhere to the perianth, blunt to rounded lobes of outer female bracts. The lobules of female bracts are constricted at base. The bilobed underleaves stand out due to their ± closed sinus, recurved margins and often connivent lobes with their lateral margins hardly to slightly conveх. The underleaves are up to two times as wide as the stem. The spores are brown and (40–)45–70(–75) × 50–75(–80) μm in size, spherical and broadly oval.

Description: —Plants in dense mats, greenish brown to purplish brown, conspicuously dull but glistening when strongly illuminated, due to mammillose protrusions of the dorsal surface of the lobes ( Fig. 2 ), gregarious, in dense mats or low cushions over bark, irregularly 1–2(–3) branched; leafy shoots to 3 cm long and 0.8–1.0 mm wide, stems 100–140(–170) μm wide. Leaves densely imbricate at most shoot length to slightly contiguous in unexposed shoot sectors; lobes entire, on main stem distinctly convex, rarely nearly flat, only at the basal margins of the lamina often recurved to the stem and forms with it angle almost 135 ° (erect-spreading), ± reniform to broadly oblique ovate, sometimes oblique oblong to broadly ovate, (315–)340–440(–560) μm long, (420–)460–650(–700) μm wide, usually 0.6–1.0 times as long as wide, dorsally ± extending beyond the farther edge of stem, base sometimes cordate, dorsal base auriculate, apex of lobes decurved, broadly rounded; margins with mammillose-papillose protrusions. Lobules inflated throughout, skull-shaped to almost cylindrical, 0.16–0.2(–0.25) the size of the lobes, (135–)160–200(–230) μm wide and (215–)240–285(–300) μm long, (1.1–)1.25–1.7 times as long as wide, oriented parallel to the stem, but the apex is oriented to the substrate, vertex very inflated, lobules barely narrowed downward into bilabiate mouth with dorsal part longer than ventral, mouth strongly compressed, except distal part. Stylus distinct, usually large, leaf-shaped or ovoid, 3–4 cells wide at base, suddenly tapered in a single-row apex of 2–4 cells long, the total length of the stylus 5–9 cells, rarely triangular, three cells wide at base and to seven cells long or filiform, one cell wide at base and three cells long, sometimes ending in slime papilla. Cells in the middle of lobes on main stem rounded penta- or hexagonal, with distinct acute to slightly bulging and sinuous trigones, with rare indistinct intermediate thickenings, (12–)16– 19(–24) μm wide, (13–)17–24(–29) μm long, smaller and nearly quadrate near margins, sometimes on apex slightly extended perpendicular to the margin and to the base, slightly extended along it, (10–)12–17 μm wide, (12–)14–17 μm long, larger to the base, (19–)24–27(–34) μm wide, 26–36(–43) μm long. Oil-bodies unknown. Ocelli lacking. Dorsal leaf cell surface unipapillose-mammillose. Formation of papillae resulted from strong thickening and merge of lateral thickened walls of mammillae. Resulting conical protuberances (12–)17–20 μm high. Underleaves (215–)230–315 μm long, 240–290 μm wide, up to twice as wide as stem, remote, nearly cuneate or obtrapezoid to nearly quadrate with slightly convex lateral margins, usually without elongated base, at base patent, bent towards the stem distally, line of insertion straight, not decurrent or with short decurrency, bilobed (0.18–)0.2–0.3 of the length, sinus often closed and indistinct, U-shaped, margins entire or rounded angular, narrowly recurved; lobes subacute, usually connivent and then crossing each other. The rhizoidal area often swollen and bistratose. Asexual reproduction unknown for certain. At upper lobe apices of several looking dead shoots, rhizoid-like uniseriate multicellular transversely septate outgrowths with cellular content were detected ( Fig. 2 : 6). They are helio- rather than geotropic. They originate from lobe apex and certain belonging to this species remains unclear. Dioicous. Androecia terminal on short lateral branches with up to six normal leaves, discoid or compactly spicate with 3–6 pairs of bracts; bracts imbricate, ventricose subequally bilobed; bracteoles at the androecial base only; vegetative proliferation from apex of androecium not observed. Gynoecia on abbreviated lateral branches or terminal on main shoots and leafy axis, with 3–4 archegonia. Interior bracts and bracteole larger than external. Female bracts with entire margins. Outer bracts divided for 0.4–0.5 their length, inner bracts divided for 0.7–0.8 their length; lobes 820–1270 μm long, 670–910 μm wide, ± concave, broadly oblong or ovate, apex broadly rounded, usually incurved to cucullate or gradually slightly narrowed to a blunt apex, their margins sometimes with unipapillose-mammillose protrusions, dorsal surface unipapillose-mammillose; lobules 720–1030 μm long, (190–)310–720 μm wide, narrowly ovate, canaliculate (sometimes longitudinally folded), margins recurved, lobules of external bracts gradually short narrowed to the blunted apex, lobules of interior bracts gradually tapered into a long usually acute apex; stylus large, ovate or lanceolate, sometimes fusiform, 3–7 cells wide at base and up to 15 cells long, suddenly tapered in the single-row apex (2–)5–11 cells long; sometimes at the base of stylus with cilia 2–3 cells at base and up 4–26 cells long or small semicircular appendage; surface smooth. Female bracteoles, 580–1060 μm long, 290–500 μm wide, with entire sometimes sinuous margins, occasionally at the base with small papillae, external bracteole almost rectangular, bilobed 0.15–0.25 the length, margins recurved, lobes triangular entire, connivent or crossing each other, at apex rounded, interior bracteoles nearly oblong to narrowly ovoid, bilobed 0.6–0.8 the length, nearly longitudinally folded, with widely recurved margins, lobes entire, parallel or crossing each other, long ± gradually tapered into a pointed apex. Perianth exserted from bracts or enclosed in bracts with only mouth emerging, obovate, surface mammillose-papillose of cells ca. 15–25 × 12–20 μm with moderately thickened walls, bulging trigones and intermediate thickenings, with three sharp keels (2 lateral, 1 ventral), apex rounded-truncate, not sunken, gradually narrowed in ± long (ca. 155 μm wide, 170–190 μm long) tubular mouth often bent to the ventral side, formed of very small evenly strongly thick-walled cells ca. 6–8 × 7–11 μm almost totally without intermediate thickenings and distinct conical protuberances of outer and inner surface, mouth entire and smooth. Capsule yellowish brown, exothecial cells ± subisodiametric, 25–37 × 35–50 μm, with coarse bulging, greenish yellow thickening at angles and on intermediate walls, cells of inner layer a little smaller, 17–30 × 20–40 μm, ± quadrangular, with slightly evenly thickened non-pigmented whitish walls nearly without trigones ( Fig. 2 : 1, 2; Fig. 4 : 5, 6). Every capsule valve with ca. 10–15 sessile elaters (15–)20–27(–32) μm in diam. with narrow brown thickenings ca. 5–7 μm wide. Spores very large but delicate, yellowish to brown, variable in size within separate capsule, spherical to broadly oval in shape, (40–)45–70(–75) × 50–75(–80) μm ( Fig. 3 ), from ca. 50 μm in diam. to 60–75(–80) × 45–75 μm. Spore surface of smaller spores (ca. 50 μm in diameter) has distinct areolation with darker brown areas (ca. 3–8 μm in diam.) of minute papillae and ± smooth light areas between them ( Figs. 3 , 4 ). Areolation in larger spores mostly less distinct and sometimes looks like a very fine net ( Fig. 3 ).

Etymology: —The specific epithet refers to the mammillose ornamentation of the dorsal surface of the leaf lobes.

Recognition and infrageneric position: — Frullania dorsimamillosa and F. chinlingensis are distinct from all known species of the genus, except New Guinean F. papillata and Tasmanian F. hattorii , in developing unipapillose-mammillose, ± narrowly conical protrusions on the dorsal leaf surface. The galeate ± skull-shaped lobules and the three-keeled tuberculate perianths instantly indicate that a representative of F. subg. Frullania is at hand. The rather large obovate underleaves with connivent lobes are similar to other related Asiatic species, like F. fengyangshanensis Zhu & So (1997: 356) or F. usamiensis Stephani (1897: 91) . Frullania dorsimamillosa , treated as F. fuscovirens Stephani (1910: 401) var. gemmipara (Schuster & Hattori in Hattori 1978: 547) Hattori & Lin (1985: 135) in the phylogenetic analyses of Hentschel et al. (2009), is resolved as belonging to a largely unresolved species complex of F. subg. Frullania that contains several other Asiatic species, F. jackii Gottsche in Gottsche & Rabenhorst (1863: 294) from Europe as well as F. brittoniae Evans (1899: 15) and F. riparia Hampe ex Lehmann & Lindenberg in Lehmann (1838: 14) from North America. In contrast to the argumentation of Hattori & Lin (1985) F. chinlingensis is morphologically closely related to F. dorsimamillosa and is in fact morphologically as well as genetically different from F. dilatata .

Distribution and ecology: —Northeastern Sichuan, Nanping and Songpan counties only; lower oroboreal zone, 2700–2930 m, in various types of forests with conifers ( Picea , Abies , Tsuga, Pinus, Juniperus ) and deciduous trees and shrubs ( Betula , Rhododendron, Salix, Acer , Philadelphus , Rosa , Sorbus , Ulmus ), on trunks and branches (incl. fallen, decorticated and decaying).

Specimens examined: —Minshan Range, Songpan County, valley of R. Fujiang 3 km E of Huanglong hotel, lower oroboreal Picea - Abies -Acer -Lonicera -Salix -Juniperus - Rosa -forest, collecting locality 5d, on a trunk of Abies , 32°45’N 103°52’E, 2900–2930 m, 09.09.1991, T. Koponen 45110, c.per., H; Minshan Range, Nanping County, Jiu-Zhai-Gou, Ze-Zha-Wa-Gou, Lake Chang-Hai, lower oroboreal Picea - Abies - Betula utilis -Juniperus -Acer - Rhododendron -forest, collecting locality 21b, on a trunk of Tsuga , 33°06’N 103°55’E, 2850 m, 15.09.1991, T. Koponen 460052, c.per., H; Minshan Range, Nanping County, Jiu-Zhai-Gou, Ze-Zha-Wa-Gou, Lake Chang-Hai, orohemiboreal Picea - Abies - Betula utilis -Juniperus -Acer - Rhododendron -forest, collecting locality 21b, on a fallen, decaying trunk, 33°06’N 103°55’E, 2850 m, 15.09.1991, T. Koponen 46077, c.per., H; Minshan Range, Nanping County, Jiu-Zhai-Gou, Ze-Zha-Wa-Gou, orohemiboreal Abies -Pinus-Betula mixed deciduous forest, collecting locality 20, on a fallen, decorticated trunk, 33°09’N 103°55’E, 2700 m, 15.09.1991, T. Koponen 46171, c.per., H; Minshan Range, Nanping County, Jiu-Zhai-Gou, Ze-Zha-Wa-Gou, orohemiboreal Abies -Pinus-Betula mixed deciduous forest, collecting locality 20, on a fallen, rotten branch, 33°09’N 103°55’E, 2700 m, 15.09.1991, T. Koponen 46187, c.per., H; Minshan Range, Nanping County, Jiu-Zhai-Gou, Ri-Ze-Gou, Natural Forest Reserve, lower oroboreal Picea -Larix - Abies -Acer - Philadelphus - Sorbus - Ulmus -forest, collecting locality 22k, on bush, 33°06’N 103°52’E, 2900 m, 16.09.1991, T. Koponen 46339, c.per., ♂, H; Minshan Range, Nanping County, Bai-He River valley 88 km SW of Nanping City. Lower oroboreal Picea forest, alt. 3000 m, 33°07’N 103 43’E. On trunk of Picea . 18.09.1991, T. Koponen 47143, H.

Note: — The type specimens of F. chinlingensis were not available for study: China, Shansi [Shaanxi], Thai-pei Mts. , Pin An Zi. 2740 m, 22.07.1963, Wei Zhi-ping 5360, 5361 (holotype WUK, isotype KUN) ; Xi Thai Bai Mts. , Ying Zi Zui, in cortice et lingo Betulae, in sylvis Abietis, 3200 m, 14.09.1963, Wei Zhi-ping 6426 .

Figures

FIGURE 1. Line drawing of Frullania dorsimamillosa sp. nov. 1, 4: Leaves. 2, 9, 13: Styli. 3: Shoot sector, ventral view. 5, 7: Median cells of lobe (mamillae omitted). 6: Female bracteoles. 8: Perianth mouth. 10: Underleaf. 11: Female shoot, ventral view. 12: Cross section of lobe. 14. Outer female bracts. 15. Perianth. 16. Marginal cells of lobe. 17. Lateral cells of perianth.All from Koponen 47143 (isotype, JE), by Yuriy S. Mamontov.

FIGURE 2. Frullania dorsimamillosa sp.nov.1: Capsule wall, inner layer.2: Capsule wall,outer layer.3: Perianth.4: Cross section through perianth mouth. 5: Plant habit, dorsal view. 6: Apex of lobe with rhizoid-like uniseriate multicellular transversely septate outgrowths. 7: Cross section of lobe. 8: Marginal cells of lobe.All from Koponen 45098 (isotype, LE), by Alexey D. Potemkin.

FIGURE 3. Frullania dorsimamillosa sp. nov. Spores. From Koponen 45098 (isotype, LE), by Alexey D. Potemkin.

FIGURE 4. Frullania dorsimamillosa sp. nov. 1–2: Spores. 3–4: Spore surface. 5: Outer capsule wall. 6: Inner capsule wall. All from Koponen 45098 (isotype, LE), by Alexey D. Potemkin and Lyudmila A. Kartseva.