Bryoxiphium Mitt., J. Linn. Soc., Bot.

Fedosov, Vladimir E., Czernyadjeva, Irina V., Ignatova, Elena A., Kuznetsova, Oxana I., Fedorova, Alina V. & Ignatov, Michael S., 2016, On the Bryoxiphium norvegicum and B. japonicum (Bryoxiphiaceae, Bryopsida)., Arctoa 25 (1), pp. 52-68 : 62

Bryoxiphium Mitt., J. Linn. Soc., Bot. 12: 24, 850. 1869.

Plants small to medium-sized, light-green, goldengreen to brownish-green, often shiny, forming loose or dense tufts. Stems 5–20[–50] mm long, erect or pendent, simple or sometimes irregularly branched, moderately tomentose basally, with large central strand and small incrassate epidermal cells; axillary hairs of 3–4(–7) cells, hyaline or with rose-violet basal cell. Leaves strongly distichous, appressed, strongly keeled, imbricate and partly covering each other, ovate-lanceolate, blunt or apiculate, becoming longer distally, acute or aristate; costa single, percurrent, short or long excurrent, with dorsal lamella, in cross-section showing a solid stereid band, well differentiated ventral epidermis and weakly differentiated dorsal epidermis; margin plane, entire, crenulate or minutele serrate near apex; lamina unistratose, cells smooth and firm-walled, with stronger thickened dorsal walls and plane to somewhat convex ventral walls, along margins in 10– 25 rows longer and narrower, with thinner walls. Dioicous. Perichaetia and perigonia terminal. Perichaetial leaves from ovate-lanceolate base narrowed into a long, flexuose, hyaline, yellowish to brownish filiform awn with serrate, crenulate or entire margins. Setae shorter than perichaetial leaves, erect, curved or flexuose. Capsules spherical to ovate or obovate, symmetric, erect or ±inclined. Annulus not differentiated. Peristome absent. Operculum remains attached to the elongated columella after dehiscence, shortly and obliquely rostrate. Spores spherical, faintly roughened. Calyptra cucullate.

KEY TO THE SPECIES OF BRYOXIPHIUM IN RUSSIA

1. Filiform awns in perichaetial and perigonial leaves 1–3(–5) mm long, with finely crenulate or subentire margins; middle stem leaves mostly obtuse, occasionally notched, shortly apiculate, apiculus formed mainly by shortly excurrent costa and partially by dorsal lamella; basal laminal cells short rectangular, with length/width ratio of 1.6–3, weakly differentiated; dorsal lamella mostly 1–2 cells high, not descending to the leaf base; spores 14–19(–23) µm ............ .......................................................... B. norvegicum

— Filiform awns in perichaetial and perigonial leaves (4–) 6–12 mm long, with sharply serrate margins; middle stem leaves obtuse, often notched and suddenly narrowed into awn to 0. 4 mm long, awn consisting of lamina, costa and dorsal lamella; basal laminal cells subquadrate, with length/width ratio of 1–1.4, forming large, more or less distinct group; dorsal lamella mostly 3–4 cells high, often reaching leaf base; spores

(17–)19–22(–24) µm .......................... B. japonicum