Marsupella vietnamica Bakalin & Fedosov, 2019

Bakalin, Vadim A., Fedosov, Vladimir E., Fedorova, Alina V. & Nguyen, Van Sinh, 2019, Integrative taxonomic revision of Marsupella (Gymnomitriaceae, Hepaticae) reveals neglected diversity in Pacific Asia, Cryptogamie, Bryologie 20 (7), pp. 59-85 : 66

Marsupella vietnamica Bakalin & Fedosov , sp. nov.

( Figs 3; 5 D-G)

Plants green to purple, without rusty pigmentation, rigid. Stem cross section with hyaloderm distinct, with external wall commonly destroying with time. Leaves subtransversely to virtually succubously inserted and oriented, strongly turned to ventral side, with plane margins, divided by sinus into 2 acute, subequal to unequal (ventral smaller) lobes. Dioicous.

TYPE. — Vietnam. Lao Cai province, Sapa district, Phan Xi Pang (also spelled Fansipan) National Park, 22°20’18”N, 103°46’39”E, 1900-2100 m alt., moist cliff in part shade, field no. V-2-101-16, leg. Bakalin V. A., 16.III.2016 (holo-, VBGI; iso-, MW)

PARATYPES. — There are several specimens from virtually the same place with the type: Vietnam. Lao Cai province, Sapa district, Phan Xi Pang (also spelled Fansipan) National Park, 22°20’18”N, 103°46’39”E, 1900-2100 m alt., moist cliff in part shade, field nos V-2-86a-16, V-2-91-16, V-2-98-16, 16.III.2016, leg. Bakalin V. A. ( MW, VBGI).

DESCRIPTION

Plants greenish, yellowish greenish, deep green to (commonly) green purple, seems to be without rusty pigmentation, rigid, 10-40 mm long and 1.5-2.8 mm wide, in loose, mostly pure patches. Rhizoids virtually absent or very few, colorless and soft. Stem brownish, rigid, slightly glossy when dry, sparsely ventrally branched (or with 1-3 lateral and ventral subfloral innovations); cross section transversely elliptic, c. 200 × 250 Μm, hyaloderm distinct, cells 12-18 Μm along margin, external wall thin and commonly destroying with time, tangential walls gradually becoming thicker inward, scleroderm very distinct, in 3-4 layers of cells, cell walls very thick than cell lumen sometimes obsolete, with well-visible median lamina, 6-15Μm in diameter (from middle lamina to middle lamina), inward suddenly become thinner (although never thin). Leaves subtransversely to virtually succubously inserted and oriented, with plane margins, insertion line arcuate dorsally and decurrent for ½ of stem width ventrally, obliquely spreading, loosely sheathing the stem in the base, strongly turned to ventral side, concave-canaliculate, when flattened in the slide ovate to slightly obliquely ovate, divided by Uto widely V-shaped sinus descending to 1/10-1/5 of leaf length into 2 acute, subequal to unequal (ventral smaller) lobes, well developed leaves 1.3-1.5 × 1.0- 1.5 mm. Midleaf cells 20-30 × 12-15 Μm, distinctly thick-walled, trigones moderate in size, convex, middle lamina hardly visible, cells in the lobe middle base 17-25 × 12-20 Μm, thick-walled, with moderate in size, convex trigones, cells along leaf margin 7-12 Μm, thick-walled, with small, concave trigones, cells near leaf base in one layer, to 55 Μm long, very thick-walled, with well-visible middle lamina; cuticle smooth throughout; oil bodies in the midleaf cells 2-3 per cell, large, nearly filling cell lumen, oblong, grayish, finely granulate. Dioicous (?). Perianth terminal, on main axis, hidden within bracts, with 1-3 lateral or ventral subfloral innovations, conical, 0.7-1.0 × 0.7-1.0 mm, loosely beaked; perigynium well developed, 1.0-1.5 of perianth length, with one pair of bracts; bracts closely sheathing the perianth in the base and overlap one another above. Otherwise not seen.