Gymnomitrion parvitextum (Steph.) Mamontov, Konstant. et Potemkin, Nova Hedwigia 106(1-2): 88, 2018

Bakalin, Vadim, Choi, Seung Se & Park, Seung Jin, 2021, Revision of Gymnomitriaceae (Marchantiophyta) in the Korean Peninsula, PhytoKeys 176, pp. 77-110 : 77

Gymnomitrion parvitextum (Steph.) Mamontov, Konstant. et Potemkin, Nova Hedwigia 106(1-2): 88, 2018 Figure 10

Marsupella parvitexta Basionym. Marsupella parvitexta Steph., Bulletin de l’Herbier Boissier, ser. 2, No. 2: 165, 1901.

Type.

Japan, Tosa , Mt. Tsutsujo, August 1898, Inoue n. 22 (lectotype (designated here): G [9470/00067518!]) .

Description.

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).

Ecology.

Acidophilic meso-xerophyte. The species occupies more or less dry substrata in exposed to (rarely) partly shaded habitats. It is commonly intermixed with Marsupella tubulosa , M. koreana , M. pseudofunckii , Gymnomiotrion faurianum , Herbertus dicranus , Anastrophyllum assimile , or (as exotic variant) with Scapania ampliata .

Distribution.

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 ( Kim and Hwang 1991; Yamada and Choe 1997) under the name Marsupella commutata . It is also reported from Gangwon-do.

Specimens examined.

Gangwon-do: Mt. Seorak , 38°08'02.8"N, 128°28'03.6"E, 908 m, 12 Oct 2010, S.S. Choi 8383 (JNU), Mt. Seorak , 38°07'34.9"N, 128°27'16.0"E, 1487 m, 12 Oct 2010, S.S. Choi 8475 (JNU); Gyeongsangnam-do: Mt. Jiri, 35°19'20.6"N, 127°44'59.4"E, 1134 m, 14 Jun 2009, S.S. Choi 3703 (JNU), 35°20'10.6"N, 127°43'42.0"E, 1820 m, 15 Jun 2009, S.S. Choi 3816 (JNU), Mt. Namdeogyu, 35°45'53.5"N, 127°40'55.5"E, 1422 m, 11 Nov 2010, S.S. Choi 8954 (JNU) .

Comment.

Easily recognizable species in most cases, although confused several times with dwarf plants of Marsupella tubulosa from which it differs in commonly present subquadrate to quadrate trigones in leaf lobe cells, almost constantly recurved leaf margin, and in the absence of perianth. Gymnomitrion parvitextum is morphologically similar to G. alpinum . The two taxa are distinct in the presence of subquadrate trigones in leaf lobe cells in G. parvitextum (absent in G. alpinum ), recurved margin (versus margin plane), shortly or barely decurrent leaf base (versus long decurent leaf base on both sides in G. alpinum ) and inability to develop red or purple pigmentation (versus such coloration common in G. alpinum ).

The bigger problem is the delimitation of Gymnomitrion parvitextum from morphologically similar and ‘semicryptic’ ( Mamontov et al. 2018) G. commutatum (Limpr.) Schiffn., disjunct, mostly northern hemiarctic species. Gymnomitrion parvitextum differs from G. commutatum in the following features: 1) pale yellowish to brownish and even yellowish-greenish coloration, but never blackish brown and rusty-brown coloration so common in G. commutatum , 2) leaves semi-distichously arranged versus leaves subimbricate, 3) leaves in the vast majority of cases with widely recurved margins, versus margin recurved narrowly and commonly near the leaf base only.

Figures

Figure 10. Gymnomitrion parvitextum (Steph.) Mamontov, Konstant. et Potemkin A female plant (fragment) B male plant (fragment) C leaf lobe apex D-G leaves H midleaf cells I gynoecium longitudinal section J stem cross section (fragment). Scale bars: a 1 mm (A, B, D-G); a 500 µm (I); b 100 µm (C, H, J). All from Choi 8475 (JNU).