Marsupella vermiformis (R.M.Schust.) Bakalin et Fedosov, Cryptogamie, Bryologie 40(7): 70, 2019

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

Marsupella vermiformis (R.M.Schust.) Bakalin et Fedosov, Cryptogamie, Bryologie 40(7): 70, 2019 Figures 6 , 7I-K

Marsupella stoloniformis vermiformis Basionym. Marsupella stoloniformis subsp. vermiformis R.M.Schust., J. Hattori Bot. Lab. 80: 72, 1996

Type.

Malaysia. North Borneo: Mt. Kinabalu National Park , S. slope, around Paca Cave, 2985 m, Mizutani, 2788 (not seen) .

Description.

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.

Ecology.

Acidophilic meso-xerophyte. In Korea, it occurs on dry well-exposed rocks in large block gravelly barrens in the crater rim of Halla Mt. Marsupella vermiformis formed pure patches or a slight admixture of Gymnomitrion faurianum or dwarf form of Marsupella tubulosa .

Distribution.

Strongly disjunct rare taxon ranging the area from southernmost Korea (Jeju-do) across China, to Malaysia and Papuasia ( Bakalin et al. 2019). The species belong to the oligotypic section Marsupella Stolonicaulon (N.Kitag.) Vaňa, which it shares with rare South and South-East Asian M. stoloniformis N.Kitag.

Specimens examined.

Jeju-do: Mt. Halla , 33°21'42.1"N, 126°32'02.8"E, 1861 m, 21 Sep 2012, S.S. Choi 120911, 120897 (JNU, VBGI) .

Comment.

The very distinctive species, superficially quite similar to Gymnomitrion pacificum Grolle due to vermicular shoots and never spreading, but closely appressed leaves, forming in female branches, a club-like structure. It is clearly different from G. pacificum in having much smaller leaves, with normally developed cells along the margin and presence of distinct perianth. The species may be mistaken for dwarf forms of arctic-alpine sub-circumpolar amphi-oceanic Marsupella boeckii (Austin) Lindb. ex Kaal. and, possible, European (amphi-Atlantic) - British Columbian (cf. Paton 1999) Marsupella stableri Spruce. However, besides distinct gaps in distribution this species differs: 1) the never spreading leaves in M. vermiformis versus at least slightly spreading in perianthous shoots in M. boeckii and obliquely spreading to squarrose in M. stableri , 2) shoot width not exceeding 140.0-170.0 μm, versus 200.0-500.0 μm in M. boeckii , and 100-400 μm in M. stableri , 3) small cells with brown colored, thickened tangential walls in stem cross section in M. vermiformis , versus large and hyaline cells in M. boeckii and M. stableri ), 4) small leaves that are wider than long, reaching at maximum 175.0 μm wide and 110 μm long, versus 200-300 μm wide in M. boeckii and distinctly longer than wide (up to 300 × 200 μm) in M. stableri , 5) very small leaf cells, 5.0-10.0 × 5.0-8.0 μm in M. vermiformis , versus 12.0-20.0 × 12.0-20.0 μm in M. boeckii and 10-16 μm in diameter in M. stableri . The distinction from M. stoloniformis (hardly possible in Korea) as well as the phylogenetic position of both is discussed by Bakalin et al. (2019).

Figures

Figure 6. Marsupella vermiformis (R. M. Schust.) Bakalin et Fedosov A gynoecium longitudinal section B, C plant habit, fragments D plant habit E stem cross section. Scale bars: a 500 µm (A-C); a 1 mm (D); b 100 µm (E). All from Choi 120911 (JNU).

Figure 7. Gymnomitrion noguchianum S. Hatt. A, B, F leaves C plant habit (fragment) D plant habit E lacerate leaf apex G cells along leaf margin H stem cross section (fragment). All from Choi 120826 (JNU); Marsupella vermiformis (R. M. Schust.) Bakalin et Fedosov I, J leaves K plant habit (fragment). All from Choi 120911 (JNU). Scale bars: a 250 µm (A-C, F); a 500 µm (D); b 100 µm (E, G-J); c 100 µm (K).