Cephaloziella grossigemma Mamontov, 2022

Cephaloziella grossigemma Mamontov , sp. nov. Figs. 1 View Fig , 2 View Fig .

Type: CHILE, Aysén Region, Aysén Province, Aysén Commune, Exploradores River valley, Parque Explorad-

1 – Tsitsin Main Botanical Garden, Russian Academy of Sciences, Botanicheskaja 4, Moscow 127276; e-mail: yurmamontov@yandex.ru, ORCID 0000-0003-3851-0738

2 – Polar-Alpine Botanical Garden-Institute of, Kola Science Centre of RAS, 184256 Kirovsk , Russia ores, near camino a Bahía Exploradores, 46°29'53.2" S, 73°09'12.1" W, 226 m a.s.l., 6.XII.2021, Mamontov & Shkurko 957-1-7472 ( MHA – holotype) GoogleMaps .

Etymology. The name reflects the presence of relatively large, multicellular gemmae, the characteristic feature of the new species.

Diagnosis. Plants golden to reddish or reddish brown, shoots very small, simple or sparingly branched, capitate to even clavate due to the masses of gemmae in the upper part of shoot, with leaves ca. 0.98–1.26 times as long as wide, 0.35–0.52 divided into two subequal lobes, often with tumid, protuberant septa over the stem and leaf cell wall intersections, and thus with crenulate appearance, with underleaves up to 0.53–0.87 the length of adjacent leaves, with reddish to reddish brown, multicellular, papillate gemmae.

Description. Plants golden to reddish or reddish brown, capitate to even clavate due to the masses of gemmae in the upper part of shoots, procumbent or ascending, usually simple (only isolated branches seen), very minute, leafy shoots 0.5–1.5 mm long, 70–130 µm wide. Branching of the Frullania - type (associated halfleaf unlobed); stolons or flagella lacking, but some shoots rather microphyllous ( Fig. 1D, H View Fig ). Stems 38–63 µm in diameter, in surface view cortical cells thin- to rather thick-walled ( Fig. 1A View Fig ), rounded-quadrate to rounded-hexagonal, 14.5–30.5 µm long, 13.3–25.3 µm wide, the cell walls intersections sometimes tending to be externally produced so that the surfaces, in profile, are seen to be covered with low, thickened, dome-like projections; stems in cross section of 7–8 cortical cells and 3 medullary cells ( Fig. 1L View Fig ), the cortical cells thin-walled, 9–20 µm in diameter, the medullary cells 11–14 µm in diameter. Rhizoids short and infrequent, whitish, scattered on the ventral side of stems. Leaves 66–93 µm long, 52–84 µm wide, 0.98–1.26× as long as wide, alternate, transversely to slightly succubously inserted, obliquely spreading to suberect, remote to subcontiguous, oblong or ovate or obovate in outline, almost plane to distinctly concave, 0.35–0.52 bifid; lobes plane to incurved, triangular, 2–4 cells wide at base, entire-margined when unmodified, the cell walls intersections often with dome-like projections similar to those seen on stem surface, so the lobe margins are typically crenulate; sinus mostly sharp, rarely semilunate; margins of leaves and underleaves modified with gemma formation bear finger-like processes of one to several cells long. Underleaves small to rather large, in upper parts of shoots ca. 0.53–0.87 the length of adjacent lateral leaves, transversely inserted, spreading or erect or appressed, entire or 0.3–0.4 bifid. Leaf cells rounded-quadrate to rounded-hexagonal, thin- to thick-walled, the laminal cells 13–17 µm long, 12–14 µm wide, the cells at base of leaf lobes 9.2–18.6 µm long, 9.2–17.5 µm wide, intramarginal cells also often with thickened dome-like projections above the walls intersections. Asexual reproduction via reddish to reddish brown (like the shoot tips) gemmae; the gemmae 21–49 µm long, 16–30 µm wide, multicellular (of 4 to 6 cells), with thickened dome-like projections similar to those in the stem and leaf cells. Sexuality and sporophyte unknown.

Ecology-Distribution. Cephaloziella grossigemma is known only from a single locality in Southern Chile, where it was collected from bark of living dwarf (stem diameter of ca. 5 cm) Nothofagus sp. trees in southern beeches-fern-moss brush. The plants are found among lichen thalli, also on shoots of other liverworts and on decaying bark pieces within patches of Anastrophyllum crebrifolium (Taylor & Hook. f.) Steph. , where an admixture of Cephaloziella serrata Steph. , Frullania fertilis De Not. and F. patagonica Steph. occur.

Studied specimens (paratypes). CHILE, Aysén Region, Aysén Province, Aysén Commune, Exploradores River valley, Parque Exploradores , near camino a Bahía Exploradores , 46°29'53.2" S, 73°09'12.1" W, 226 m a.s.l., 6.XII.2021, Mamontov & Shkurko 957-1-7471, 957-1-7477 ( MHA) GoogleMaps .