Corresponding author: Seung Se Choi (
Academic editor: M. Renner
This paper provides a revision of
Bakalin V, Choi SS, Park SJ (2021) Revision of Gymnomitriaceae (Marchantiophyta) in the Korean Peninsula. PhytoKeys 176: 77–110.
The main goal of the present paper was to revise
Owing to the data at hand, it is known that
This paper provides the descriptions compiled based on the study of specimens collected in Korea and to a lesser extent, the types. The morphological descriptions are supplemented by figures, list of specimens examined, discussion on ecology, distribution, and, in some cases, the taxonomy and morphology. The distribution within the Korean Peninsula, described using official regionalization, extended throughout the Korean Peninsula despite covering different countries (Fig.
The regionalization (provinces) of the Korean Peninsula accepted in the present paper. Abbreviations:
The morphological descriptions for family and genera use features known in the taxa recorded in the Korean Peninsula. The taxa reported in the literature, but not revealed in the present revision (and suspected to be erroneously reported) are keyed out, in square brackets and are not supplied with descriptions; rather they are briefly discussed in the section ‘Excluded taxa’. After the accepted name of the species, only a few common synonyms are provided, with an emphasis on names previously applied to plants from the Korean Peninsula.
Plants rigid to soft, variously colored. Rhizoids sparse to dense, mostly colorless, rarely purple. Stem with differentiation into scleroderm, hyaloderm and inner tissue or without differentiation (then mostly pachydermous in structure). Leaves shallowly emarginate to bilobed (not more than 2/5 of leaf length) into equal to unequal lobes. Underleaves absent (present in
The above description is applicable to the
1 | Plants with well-developed perigynium and reduced, but always distinct perianth, loosely leaved, leaves mostly (excluding androecious branches) not imbricate, if imbricate ( |
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– | Plants with strongly reduced to absent perigynium and virtually absent perianth, leaves wider than stem, with margin plane or revolute, commonly imbricate, if not ( |
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Plants forming loose patches, commonly ascending or rarely creeping in habitats with strong insolation and incrusted by soil particles, deeply (deep green, brown-green, brown purple, blackish brown) to pale (yellowish, brownish, greenish and their combinations) colored, merely rigid, varying in size from 0.5 to 2.0 mm wide and 5.0–50.0 mm long. Rhizoids sporadic to solitary, although invariably present in ventral geotropic leafless stolons, colorless to grayish and soft-textured, or rarely and solitary purple and rigid. Stem with common ventral branching and rare lateral branches, with characteristic geotropic stolons present in the majority of taxa; in cross section mostly differentiated into three strata: hyaloderm, scleroderm and inner tissue. Leaves transversely or nearly so inserted, obliquely to erect spreading from sheathing or not sheathing base, concave to canaliculate and strongly conduplicate, divided by evident but not deep sinus into two equal to strongly unequal lobes with rounded to acute apices. Underleaves absent. Cells in the leaf in the most taxa pachydermous with large convex trigones, unequally thickened along margin and having smooth cuticle; oil-bodies few in number, (1–)2–3(–4) per cell, finely granulate to papillose or almost smooth, rarely with central eye. Dioicous. Androecia intercalary, spicate, antheridium stalk biseriate (rarely uniseriate near the base). Perianth short, but always developed, onion-shaped or conical, wider than long, mostly hidden, but rarely emergent from bracts; perigynium well developed, commonly 2–3 times longer than the perianth, with (1–)2 pairs of bracts. Elaters 2–4-spiral, spores brownish, papillose.
This paper accepts recent emendations for the circumscription of
In the specimens examined section, we cite only one specimen per locality (or 2 to 3, if they were collected at different elevations) with the intention of economizing space. Only specimens from the Korean Peninsula are cited.
1 | Plants with strongly distichously arranged and keeled to narrowly canaliculate leaves, lobe apices acute to obtuse |
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– | Plants not strongly distichous, concave to canaliculate (never conduplicate), lobe apices acute to rounded |
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2 | Plants noticeable dilated to perianth, leaves conduplicate, lobes unequal, with margin plane, leaf keel distinct |
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– | Plants slightly or not dilated to the perianth, conduplicate to canaliculate, lobes unequal to subequal, with margin plane to recurved, leaf keel distinct or not |
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3 | Leaf lobes subequal, leaf margin commonly undulate and never narrowly recurved, leaf lobes commonly turned to dorsal side, midleaf cell with thick walls and relatively small and concave trigones |
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– | Leaf lobes unequal, leaf margin recurved, never undulate, leaf lobes never turned dorsally, midleaf cells with thin to slightly thickened walls and moderate to large, convex trigones |
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4 | Plants vermiform, with leaves narrower than the stem (except very apex) and very tightly appressed to the stem |
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– | Plants with leaves spreading, distinctly wider than the stem |
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5 | Leaves lax, sometimes shallowly undulate at margin, divided by sinus descending at most for 2/5 of the leaf length, plants with green to brownish coloration (never red), hyaloderm in stem cross section with cells twice as large as inner cells, oil bodies not biconcentric [not confirmed for Korea] | [ |
– | Leaves merely rigid, with recurved margins (sometimes obscurely so or only near the leaf base), distinctly concave, never undulate at margins, divided by sinus descending at most for 1/5(-1/4) of the leaf length, plants sometimes red, hyaloderm cells in the stem cross section less 1.5 times as inner cells, oil bodies biconcentric or not |
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6 | Oil bodies without central eye or with very small eye, plants’ color varying in exposed places to brown and rusty, but never red and purple |
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– | Oil bodies always or at least in 50% of oil bodies with central eye, plants commonly purple in exposed places |
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Japan, Miyokosan, U. Faurie 75 (
Plants in rather loose patches, rigid to more soft, erect or nearly so, mostly deep green to brownish green in color, but with many other variants intergrading to yellowish-brownish, yellowish, and pale greenish (later only in shaded wet places) or to deep brown and rusty pigmentation in insolated moist habitats; mostly 1.2–1.6 mm wide and 7.0–15.0 mm long, with small forms starting from 0.75–1.0 mm wide and robust varying to 1.5–2.2 mm wide. Branching lateral (rare) or ventral as subfloral innovations (more common), stem transversely elliptic in the cross section, 200.0–300.0 μm high (extreme variants not included) and 250.0–350.0 μm wide; outer cells (hyaloderm) nearly thin, with small trigones, 15.0–25.0 μm along margin, scleroderm in 3–4 layers, with cells slightly smaller, very thick-walled, with lumen just 8.0–11.0 μm, inner cells (10.0–)12.0–20.0 μm, thin- to slightly thickened, with moderate in size, triangle to concave trigones. Rhizoids sparse to virtually absent, mostly colorless to brownish, in unclear obliquely to erect spreading fascicles, rarely (and very few in number) separated and deep purple. Leaves mostly contiguous and loosely enclosed one to another, to subimbricate or nearly distant in lax modifications, concave to canaliculate-concave, transversely inserted, evidently sheathing the stem in the base and obliquely to erect spreading above, transversely, subtransversely or (more rarely) obliquely oriented, with margin commonly narrowly recurved, at least in lower half of the leaf; transversely elliptic to orbicular and widely ovate in shape, mostly 500.0–750.0 μm long and 550.0–1050.0 μm wide, reaching in lax forms 1500.0–2250.0 × 1550.0–2750.0 μm, divided by sinus descending to 1/7–1/5(1/4) of leaf length into two nearly equal to subequal lobes; sinus varying from narrowly to widely
Acidophilic hygro- to hydrophyte, occupying various habitats, from very wet (and even submerged) shaded cliffs near running water to moist mineral substrata in full sun. In moist and sunny habitats, robust phases are formed (then commonly acquiring deep rusty-brown pigmentation), where it is associated with
Montane temperate Kurils-Japanese-Korean endemic species is known in northern and middle Japan (until Shikoku), South Korea and South Kurils (Iturup Island), likely more widely distributed, at least to Kamchatka Peninsula in in the north. In Korea, Jeju-do, Chungcheongbuk-do, Chungchengnam-do, Gyeongsangnam-do, Gangwon-do, Jeollabuk-do and Jeollanam-do (
This species was regarded as the variety within
South Korea, Gyeongsangnam-do, Jiri Mts., National Park, 7.V.2015, Bakalin V. A. Kor-28-4-15 (
Plants in loose mats, more or less rigid, strongly distichous, brownish green to deep green, brownish greenish and yellowish brownish, also brown with rusty tint to brown purple, 500.0–1100.0 μm wide and 10.0–25.0 mm long. Rhizoids absent or very few, but common in geotropic stolons, colorless to grayish, obliquely to erect spreading. Stem rarely produces normal ventral branches, whereas commonly with ventral geotropic leafless stolons, almost always with 1–2 subfloral ventral or lateral innovations near gynoecia; stem cross section nearly rounded to slightly transversely elliptic, differentiated into strata, with outer layer cells 10.0–13.0 μm along margin, unequally thickened, but with thin and easily destroying external side, with moderate to small concave trigones; scleroderm well developed, in 2–3 layers, walls very thick, sometimes with visible median lamina, 7.0–10.0 μm in diameter, but with lumen only 3.0–6.0 μm in diameter, trigones moderate to large, concave; inner cells irregular in shape, 10.0–15.0 μm in diameter, walls thickened, trigones moderate, concave. Leaves distichously arranged, transversely to subtransversely inserted, obliquely spreading and subtransversely oriented, margins narrowly recurved in the both (dorsal and ventral) sides, narrowly canaliculate (looks conduplicate) with ‘keel’ slightly arched or nearly straight (in poorly developed phases), divided by gamma-shaped sinus into two strongly unequal gibbous lobes, lobe apices acute to obtuse. Cells in the midleaf mostly oblong, rarer subisodiametric, 7.0–20.0 × 7.0–13.0 μm, walls thickened, trigones large, triangle to convex, cuticle smooth, cells along lobe margin 5.0–10.0 μm, with unequally thickened walls, trigones small to moderate in size, concave, cuticle smooth; cells in the lobe middle 7.0–15.0 × 7.0–12.0 μm, with walls thickened to thin, trigones large and convex, sometimes confluent; oil-bodies (1–)2(–3) per midleaf cell, not biconcentric, spherical to oblong, ca. 5.0–7.5 × 5.0 μm. Dioicous. Androecia intercalary, with 2–3 pairs of bracts (but adjacent 1–2 pairs of ‘sterile’ leaves are similar with bracts that gives the impression of long androecia), spicate, bracts cupped to spoon-shaped, with recurved margin, suborbicular and lacerate when flattened in the slide, divided by
Acidophilic to neutro-tolerant meso- to hygrophyte. The ecology of this species is somewhat similar to that of
Montane temperate species, known from only the southern part of the Korean Peninsula, but probably spreading northward. In Korea, Jeju-do, Chungchengnam-do, Gyeongsangnam-do, Jeollabuk-do and Jeollanam-do (
This distinctive species is one of the most common Korean
Distinction of
Features |
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Lobes comparative size | unequal | more or less equal | more or less equal | subequal to slightly unequal | unequal | unequal |
Leaf margin | Plane | recurved (at least in basal part) | plane to undulate | plane to indistinctly recurved near base | plane | recurved |
Lobe apex | acute to obtuse | rounded | acute to obtuse | acute to obtuse | rounded | acute to obtuse |
Cell wall in the midleaf | thin to slightly thickened | thin to slightly thickened | thick | thin to slightly thickened | thin to slightly thickened | thin to slightly thickened |
Trigones in the midleaf | convex | convex | concave | convex to triangle | convex to triangle | convex |
Leaf basal part | unistratose | unistratose or bistratose in large phases | bistratose | unistratose | unistratose | unistratose |
Leaf shape | strongly conduplicate | concave-canaliculate to concave and nearly flattened | strongly conduplicate | canaliculate-concave to concave and canaliculate | canaliculate-concave | canaliculate |
Purple shoot pigmentation | very rare | sometimes present | common in Japan, but rare in Korea | very common | common | common |
Japan, Echime Prefectura, Omogo, 27 July 1940,
Plants in loose mats, more or less rigid, erect to ascending, strongly distichous, brownish green to deep green, rarely brown with rusty, purplish or reddish tint near apices, strongly dilated to the perianth, 500.0–600.0 μm wide in normally developed part, with common depauperate plants (in shady and dry habitats) starting from 150.0 μm wide, near perianth much wider and reaching 1100.0 μm, 10.0–25.0 mm long. Rhizoids virtually absent with exception of leafless geotropic stolons, where common, obliquely spreading, separated or united into unclear fascicles. Stem branching ventral and (more commonly) lateral, as subfloral innovations and ventral leafless geotropic stolons that sometimes transform into normal branches; stem cross section transversely elliptic, differentiated into strata, outer layer with walls unequally thickened (but external wall thin), 12.0–25.0 μm along margin, trigones moderate, concave, scleroderm cells 10.0–13.0 μm in diameter, with strongly thickened walls and moderate in size, concave trigones, gradually transformed to inner tissue, cells in inner part 10.0–18.0 μm in diameter, walls thickened to almost thin, trigones moderate, concave. Leaves transversely inserted, not or barely sheathing stem in base, obliquely spreading, transversely oriented, evidently keeled-conduplicate with plane margin, keel straight to slightly arched or suddenly turned downward near the end, leaves contiguous to distant, rarely enclosed one to another, 220.0–430.0 μm long and 300.0–600.0 μm wide, obliquely transversely elliptic, divided by
Acidophilic meso- to hygrophyte taxon. The species occupies dry to moist cliffs, rarely wet rocks as well as stones near streams, in open to (more commonly) partly shaded places. It grows together with various
Temperate Montane East Asian species, aside from Korea known from China (Taiwan, Zheijiang (the report from the latter is based on
This is a distinctive species belonging to the group of
Japan, Unzen, 5 Mar 1895,
Plants merely rigid, forming loose patches, deep green-brown, purple-brown, purple-green, or rarely greenish (actually plants extracted from the patch yellowish brownish in general, but with purple-rusty coloration in apices and upper parts of insolated leaves that gives expression of purple-brown color of patch), or yellowish greenish, pale brownish with purple tint in apical parts, rarer brownish greenish without purple or rusty pigmentation; 0.6–1.2 mm wide (the largest lax plants up to 1.3–1.5 mm) and 5.0–15.0 mm long. Rhizoids nearly absent or few, colorless. Stem brownish, not branched or branched as ventral leafless stolons (rarely becoming to normal branch) or more commonly as subfloral ventral or lateral innovations; transversely elliptic in cross section, 160.0–180.0 μm high and 200.0–250.0 μm wide (depauperate shoots omitted), differentiated into strata; hyaloderm with external wall thin, radial walls thin to unequally thickened (becoming thicker inward), inner wall thick, 15.0–20.0 μm along margin; scleroderm in (1–)2 rows of cells, cells thick-walled, but not so strongly as in
Acidophilic meso- to hygrophyte. The species occupies sandy soils and mineral substrates, over wet to moist, and sometimes mesic cliffs, being most common along streams near running water. In drier habitats, it is commonly associated with
The distribution of the species is confined to insular and peninsular areas in Amphi-Pacific Boreal and Temperate Eastern Asia, while the records provided by Bakalin, (2010),
This species may be confused with at least three other species:
Malaysia. North Borneo: Mt. Kinabalu National Park, S. slope, around Paca Cave, 2985 m, Mizutani, 2788 (not seen).
Plants strongly vermicular, forming loose patches, brown to blackish brown, without red or purple pigmentation, orbicular in cross section, 100.0–140.0 μm in diameter, 3.0–6.0 mm long, freely ventrally branched, from leafless brownish to whitish in color densely ventrally branched rhizome. Rhizoids virtually absent, to solitary, colorless, obliquely spreading, short (less than 100.0 μm long). Stem 100.0–170.0 μm in diameter, orbicular in cross section, outer layer cells with external wall thin to obscurely thickened, tangential walls subequally thickened, trigones small, concave, walls brown in color, 6.0–10.0 μm in diameter, inner cells with walls unequally thickened, walls colorless, trigones moderate in size, concave. Leaves appressed to the stem (commonly lacerate into two segments when try to detach), transversely inserted and oriented, not decurrent, widely triangular, 65.0–110.0 μm long and 90.0–175.0 μm wide, divided by V-shaped sinus descending to 2/5–1/2 of leaf length into two subequal triangle lobes with acute apices. Cells in the midleaf 5.0–10.0 × 5.0–8.0 μm, walls moderately thickened, trigones small, concave; cuticle smooth; oil-bodies 1–2 per cell, spherical, 2.0–3.0 μm in diameter. Dioicous. Pants suddenly dilated to the perianth, to form club-shaped structure, perianth completely hidden within bracts, nearly conical, 75.0–100.0 μm long and 200.0–230.0 μm wide, smooth, perigynium 120.0–150.0 μm long, with one pair of bracts; bracts nearly orbicular to orbicular-triangular in shape, ca. 250.0 × 250.0 μm, covering perianth and then occlude one with another.
Acidophilic meso-xerophyte. In Korea, it occurs on dry well-exposed rocks in large block gravelly barrens in the crater rim of Halla Mt.
Strongly disjunct rare taxon ranging the area from southernmost Korea (Jeju-do) across China, to Malaysia and Papuasia (
The very distinctive species, superficially quite similar to
Japan. Kagoshima Pref., Yakushima Island, Horikawa, 11895 (not seen).
Plants in loose patches, deep green-brown, yellow-brown, yellowish brownish, rarely with purple tint, (1.0)1.5–2.1 mm wide and 15.0–50.0 mm long, rigid. Rhizoids nearly absent to very sparse, colorless, obliquely spreading, however common in basal part of ventral branches and leafless stolons. Stem easily laterally and ventrally branched giving start to normal branches or geotropic leafless stolons; stem transversely elliptic in cross section 210.0–240.0 μm high and 250.0–320.0 μm wide, distinctly differentiated into strata, hyaloderm cell walls moderately thickened (but external wall thin), with small concave trigones, 17.0–25.0 μm along margin, scleroderm cells with very thick walls and visible median lamina, 12.0–17.0 μm in diameter, but with lumen disappearing or only 2.0–6.0 μm in diameter, inner cells with moderately thickened walls and moderate in size, concave trigones, 10.0–15.0 μm in diameter. Leaves strongly conduplicate and distichously arranged that gives ‘scapanioid’ appearance, contiguous to imbricate, as a rule enclosed one to another, obliquely spreading and transversely oriented, when flattened subquadrate, rectangular or obovate to suborbicular (mostly wider than long, but sometimes longer than wide), bistratose in lower 1/5–1/6 of the leaf length, 675.0–1250.0 μm long and 800.0–1500.0 μm wide, commonly dorsally secund, divided by
Acidophilic hygro- to hydrophyte. The species occurs on wet cliffs at a distance from watercourses or on stones washed with sluggishly running water in partly shaded habitats in the middle elevation of mountains covered with evergreen to deciduous broadleaved forests. Commonly, the species forms pure patches or rarer, associated with
South temperate to subtropical Montane East Asian endemic species known in China (Anhui, Fujian, Guangdong, Jiangxi, Zhejiang), the southern part of the Korean peninsula (the report by
This large and beautiful species is a rarity within the Korean flora and is known only from a few localities. Unlike Japanese populations, the Korean populations acquire purple to red pigmentation as an exception. The main characteristic of the species includes nearly equal lobes that do not have recurved margins, but commonly undulate and/or turned antically. Another characteristic feature is the absence of a distinctly sheathing leaf base. Dwarf plants of
Plants worm-shaped to ribbon-like, with densely imbricate leaves or similar to
This treatment follows the recent emendations
1 | Leaves entire to emarginate, never distinctly bilobed |
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– | Leaves distinctly bilobed |
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2 | Plants from huge rhizomatous base, leaved part clavate, leaves densely imbricate, leaf margin plane and discolored |
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– | Plants lacking huge rhizomatous base, not or scarcely clavate, leaves loosely spreading, margin not discolored, revolute (at least in base) |
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3 | Branches vermicular, brownish to nearly brown (sometimes pure green in Europe, but such forms were never seen in Eastern Asia), cells along leaf margin nearly thick-walled, with large and convex trigones, never erose [not confirmed for Korea] | [ |
– | Branches dorsiventrally compressed, whitish to grayish, rarely yellowish brownish, cells along leaf margin thin-walled |
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4 | Leaves with acute lobes, cells along lobe margin thin-walled, with trigones distinct, mostly with sharply verruculose cuticle (cf. Bakalin, 2016, Figure |
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– | Leaves with rounded lobe apices, cells along lobe margin thin-walled (easily destroyed in older parts), trigones virtually absent, cuticle smooth [not confirmed for Korea] | [ |
5 | Black to black-brown plants, trigones in the midleaf concave, in apical part of the leaf triangle and never quadrate, leaf margin always strongly revolute, leaf cuticle coarsely verrucose [not confirmed for Korea] | [ |
– | Plants yellowish, yellow-brown, and yellowish green to somewhat whitish green, rarely blackish brown, trigones in the midleaf bulging, in lobe apex commonly quadrate and giving appearance of chessboard, margin recurved to somewhat plane in upper part of the leaf, leaf cuticle verrucose to smooth |
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6 | Plants yellowish green to whitish green, somewhat dorsiventrally compressed, leaves distichously arranged, leaf margin crenulate due to projecting cell walls, commonly with hemispherical papillae |
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– | Plants blackish brown, not compressed dorsiventrally, leaves sheathing the stem, not distichous, leaf margin entire, cuticle smooth to finely verrucose, never with hemispherical papillae |
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Austria. Tirol, Montefuner Tal, 2300 m, 1868, leg. Jack, (
Plants in loose patches, rigid, slightly glistening when dry, hardly soaking, blackish brown, without red or purple pigmentation, 450.0–700.0 μm wide and 5.0–15.0 mm long. Rhizoids nearly absent, with the exception of ventral stolons, where common (sometimes dense), colorless or with admixture of solitary deep purple. Stem brownish to whitish (commonly whitish in geotropic stolons), branching lateral or ventral, rather common as subfloral innovations, also as ventral stolons with scale-like leaves; transversely elliptic in cross section, 120.0–140.0 μm high and 130.0–150.0 μm wide, composed by rather uniform cells, outer layer cells 12.0–20.0 μm along margin, slightly larger than inner cells, with brownish and unequally thickened walls and large (sometimes confluent) concave trigones; inner cells 10.0–18.0 μm, walls unequally thickened, colorless, trigones large, triangular to convex. Leaves imbricate, enclosed one to another, concave-canaliculate to concave and spoon-shaped, transversely inserted, sheathing the stem, loosely obliquely spreading and transversely oriented, sometimes secund dorsally, elliptic to loosely widely ovate or obovate or nearly rectangular, 320.0–500.0 μm long and 300.0–450.0 μm wide, margin recurved to plane in upper part of the leaf, divided by V-shaped sinus, with commonly recurved basal part of the sinus, descending to 1/4–1/3 of leaf length, into two equal to subequal lobes, lobes triangular to gibbous with obtuse to acute, rectangular or even rounded apex. Cells in midleaf 8.0–20.0(–23.0) × 8.0–17.0 μm, walls thin, trigones large, bulging, cuticle smooth to finely verrucose; cells along margin 6.0–11.0 μm, with thin to thickened walls, trigones large, bulging or convex, sometimes confluent, in robust phases external wall protruding, the margin then crenulate, cuticle smooth to verrucose; cells in lobe middle 7.0–13.0 × 7.0–12.0 μm, thin-walled, with large bulging or quadrate and confluent trigones (gives expression of chessboard), cuticle smooth to verrucose.
Acidophilic meso-xerophyte, the species occupies more or less dry substrata in exposed to (rarely) partly shaded areas. In the study area was intermixed with
The species is very similar to
Japan. “Tidesan” 29 August, 1898, Faurie 212 (
Plants in loose mats, more or less soft, leaved part of shoot distinctly clavate, from rhizomatous base, dorsiventrally compressed, whitish to whitish green and pale brownish in general aspect, due to discolored leaf margins that gives expression of white pigmentation, although middle part of leaves maybe greenish to brownish green, 250.0–800.0 μm wide (large plants to 1000.0 μm wide) and 5.0–15.0 mm long. Rhizoids virtually absent to sparse in leaved shoots, but rather common in rhizomatous base and geotropic leafless stolons, soft, colorless, in indistinct obliquely spreading fascicles, rarely with admixture of solitary purple in color and rigid rhizoids. Stem in leaved part branched as subfloral innovations, while in rhizomatous base freely and variously branched, leafless geotropic stolons infrequent, originated mostly near base of leaved part of shoot; cross section not differentiated into distinct layers, nearly orbicular to slightly transversely elliptic, 140.0–160.0 μm high and 170.0–190.0 μm long; outer cells slightly larger than inner, 20.0–30.0 μm along margin with walls thick (but external wall thinner), trigones moderate in size, concave; inner cells irregular in shape, with flexuous thickened walls, 15.0–23.0 μm in diameter, trigones moderate in size, concave. Leaves densely imbricate, enclosed one to another, obliquely spreading, transversely oriented, not sheathing in the base, ovate to obliquely ovate and widely triangular in shape, 350.0–700.0 μm long and 400.0–650.0 μm wide, divided by V-shaped sinus descending to 1/7 (smaller plants from drier habitats) – 1/6–1/5 of leaf length into two equal to subequal triangular to loosely gibbous lobes with acute to obtuse apes and distinctly crenulate margins. Cells in the midleaf subisodiametric to rectangular and irregularly oblong, 17.0–30.0 × 17.0–23.0 μm, thin-walled, with moderate to large, convex trigones, cuticle smooth; cells along margin 12.0–18.0 μm, thick- to merely thin-walled, with thinner external wall, discolored in 1–5 cells rows almost to the leaf base, with trigones moderate to small in size, concave, cuticle sharply verruculose; cells in lobe middle 15.0–30.0 × 12.0–(18.0)20.0 μm, walls thin to thickened, trigones varying from moderate to small and from concave to bulging (if trigones become bulging cell walls become thinner), cuticle verruculose to smooth. Dioicous. Androecia intercalary. Perianth and perigynium absent, bracts similar to leaves, but larger, more deeply divided (up 15–1/4 of the length), with somewhat diverging and spreading, rarely erose-dentate lobes.
Acidophilic mesophyte. The species occupies mesic to moist (rarely wet) cliffs in open places, and rarely occurs in partly shaded habitats, producing thinner forms with not densely appressed leaves. In drier habitats, it is commonly associated with
East Asian oro-boreal species widely distributed in northern to middle Japan (although a rarity as far as Yakushima Island), abundant in southern Kurils. Within the Asian mainland, known from Sikhote-Alin mountain system, stretching to South Korea until Jeju-do. Likely to be found in North-East China (at least in Changbai Mountain). Previous reports of
The whitish plant coloration, distichous leaf arrangement, and distinctly bilobed leaves easily help in recognizing
Japan. Tottori Prefecture, Daisen Mt., 1400 m, on volcanic rocks, 8 August 1947, A. Noguchi s.n. (
Plants in loose mats, more or less soft, leaved part of shoots distinctly clavate from rhizomatous base, dorsiventrally compressed, whitish to whitish green or almost completely white, immersed to soil and incrusted by soil particles, 250–350 μm wide and 500–700 μm long in leaved part, rhizomatous part ca. 3–5 mm long. Rhizoids common to (in rhizomatous base) dense, erect to obliquely spreading, separated or in unclear fascicles. Stem freely ventrally branched in the base of leaved part and variously and feely branched in rhizome; slightly transversely elliptic in cross section, ca. 100 μm high and 120 μm wide, without evident differentiation into layers, outer cells 12–15 μm along margin, with thick walls (become noticeable thinner to thin in ventral epidermis), with moderate in size, concave trigones, inner cells 7–13 μm in diameter, irregular in shape, with thickened walls and moderate to small in size concave trigones. Leaves densely imbricate, transversely inserted, not sheathing at base, transversely oriented, widely ovate-lingulate to widely triangular, cupped to spoon shaped, lacerate when flattened, 220–330 μm long and 270–500 μm wide, with rounded to emarginate apex and entire to crenulate margin. Cells in the midleaf subisodiametric (mostly quadrate) to oblong (mostly rectangular), 12–25 × 12–20(23) μm, walls thickened, trigones small to moderate in size, concave, cuticle smooth; cells along leaf margin 5–15 μm, mostly elongate perpendicularly to the margin, walls unequally thickened, trigones small to moderate, concave. Dioicous. Androecia intercalary, with cupped and loosely imbricate bracts. Perianth and perigynium absent, perichaetial area of the shoot distinctly wider than below.
Acidophilic meso-xerophyte. The species occupies dry to mesic fine soils in well-exposed places at higher altitudes. It is commonly associated with dwarf xeric forms of
Temperate Montane Eastern Asian endemic species with distribution confined to Japanese Honshu and Kushu as well as the southern tip of Korea (Jeju Island).
Due to the presence of entire to emarginate leaves,
Japan, Tosa, Mt. Tsutsujo, August 1898, Inoue n. 22 (
Plants in loose patches, rigid, slightly glistening when dry, hardly soaking, yellowish, yellow-brown and yellowish greenish, without red or purple pigmentation, 450.0–1000.0 μm wide and 3.0–20.0 mm long. Rhizoids nearly absent, with the exception of ventral stolons, where common (sometimes dense), colorless or with admixture of solitary deep purple. Stem brownish to whitish (commonly whitish in geotropic stolons), branching lateral or ventral, rather common as subfloral innovations, also as ventral stolons with scale-like leaves; transversely elliptic in cross section, 125.0–175.0 μm high and 150.0–190.0 μm wide, composed by rather uniform cells, outer layer cells 12.0–20.0 μm along margin, slightly larger than inner cells, with brownish and unequally thickened walls and large (sometimes confluent) concave trigones; inner cells 10.0–18.0 μm, walls unequally thickened, colorless, trigones large, triangle to convex. Leaves distichously spreading, enclosed one to another, concave-canaliculate to concave and spoon-shaped, transversely inserted, barely or not sheathing the stem in the base, transversely oriented, sometimes secund dorsally, elliptic to loosely widely ovate or obovate or nearly rectangular, 360.0–670.0 μm long and 500.0–625.0 μm wide, margin recurved to plane in upper part of the leaf, divided by V-shaped sinus, with commonly recurved basal part of the sinus, descending to 1/4–1/3 of leaf length, into two equal to subequal lobes, lobes triangular to gibbous with obtuse to acute, rectangular or even rounded apex. Cells in the midleaf 8.0–20.0(–23.0) × 8.0–17.0 μm, walls thin, trigones large, bulging, cuticle smooth; cells along margin 6.0–11.0 μm, with thin to thickened walls, trigones large, bulging or convex, sometimes confluent, in robust phases protrudent in external wall that gives expression of crenulate margin, cuticle smooth to verrucose; cells in lobe middle 7.0–13.0 × 7.0–12.0 μm, thin-walled, with large bulging or quadrate and confluent trigones (gives expression of chessboard), cuticle smooth to with hemispherical papillae. Dioicous. Androecia intercalary, with 2–4 pairs of bracts (adjacent pairs of leaves somewhat similar in shape with bracts that may be misinterpreted as bracts), spicate, 1(–2)-androus, stalk biseriate, ca. 100.0 μm long, body nearly spherical ca. 130.0–140.0 μm in diameter; bracts spoon-shaped, with more widely than in leaves recurved margin, widely ovate-trapezoidal when flattened. Perianth entirely absent; perigynium absent or very low (up 100.0 μm long); bracts similar to leaves, but longer; commonly with 1–2 subfloral innovations becoming into normal branch and fertilized soon again or forming flagelliform brown colored branch (in drier habitats).
Acidophilic meso-xerophyte. The species occupies more or less dry substrata in exposed to (rarely) partly shaded habitats. It is commonly intermixed with
East Asian oro-boreal taxon, known in areas adjacent to the Korea from the Russian Far East, Japan, and likely should be found in China. It was recorded in Korea from Gyeonggi-do, Gyeongsangnam-do, Hamgyeongnam-do (
Easily recognizable species in most cases, although confused several times with dwarf plants of
The bigger problem is the delimitation of
The taxon was recorded for North Korea (Gangwon-do, Hamgyeongnam-do, cf.
All reports of this taxon belong to
This taxon was recorded for Jeju-do (
This species was recorded on the Korean Peninsula from North Korea (Yanggang-do, cf.
This work was partially supported by a grant from the 5th National Ecosystem Survey of National Institute of Ecology (NIE), funded by the Ministry of Environment (MOE) of the Republic of Korea (NIE-A-2021-01). The laboratory work of VB was partially supported by the grant from the Russian Foundation for Basic Researches (20-04-00278). We thank two anonymous reviewers for comments that improved the manuscript.
* The nomenclature of taxa mentioned in the ‘Ecology’ section follows Söderström et al. (2016).