Fossombronia pseudointestinalis Cargill, 2021

Fossombronia pseudointestinalis Cargill View in CoL , sp. nov. Figs. 3–9 View Fig View Fig View Fig View Fig View Fig View Fig View Fig

Diagnosis. Plants are vegetatively similar to Fossombronia intestinalis with which it shares concave overlapping leaves, giving the plants a tube-like appearance. Fossombronia pseudointestinalis , however, is a brighter green often with fuchsia tinges along margins compared to the pale green frequently seen in F. intestinalis . Fossombronia intestinalis plants are also broader and smaller than those of F. pseudointestinalis . Distally, the spores of F. pseudointestinalis have thick vermiculate bands and nodules, no reticulate patterning or areolae and with large, thick verrucae on the proximal face. Spores of F. intestinalis are reticulate distally, the areolae bordered by tall thin lamellae and with patterns of almost flat irregularly shaped verrucae and lamellae over the proximal face.

TYPE. Australia: New South Wales. Bendick Murrell National Park, NNE of Young, 34°04’25.2"S, 148°25’55.2"E, 547 m a.s.l. Rounded crest of ridge. Brown earth. Callitris endlicheri low open forest with scattered emergent Eucalyptus . Liverwort growing on moist soil in slight run-on areas, with moss and Asterella drummondii . Frequent. 19 July 2020, leg. R.W. Purdie & M.A. Fagg, Coll. No. 12052 ( holotype: CANB 918520; isotype: NSW).

Plants observed in nature.

Description. Plants in nature gregarious, forming small, scattered patches, bright green (RHS 144A, yellow-green group and with fuchsia tinges RHS 59B in female plants), prostrate, up to 7.0 mm long, 1.5–2.55 mm wide, 1.3–2.5 mm in height; sparingly branched, unbranched or 1x furcate, with branches ventral-lateral. Leaves closely imbricate, erect, often with shallow ribs or crests or less frequently, large leaf-like lobes, protruding out perpendicular to main leaf, not running the length of the leaf, variable in length, or without crests, concave, inserted longitudinally, succubous with antical margin decurrent on some leaves in male plants, oblate to quadrate in female plants, oblate to quadrate to lingulate in male plants, 0.8–1.95 mm long × 0.6–3.1 mm wide, 0.45– 1 Royal Horticultural Society 1995. ‘RHS Colour Chart.’ The Royal Horticultural Society: UK

2.8 mm wide at leaf insertion; margins shallowly lobed, with lobe shape variable; margins entire to irregularly dentate; leaf apex rounded or truncate; median leaf cells polygonal isodiametric to elongate, 32.5–137.5 µm long × 20–62.5 µm wide, without conspicuous trigones; numerous segmented oil bodies in all cells; marginal cells undifferentiated along the apex of leaves, becoming elongated along the sides. Stems ovoid to plano-convex; 400– 1070 µm wide × 500–1180 µm high. Ventral scales not observed. Rhizoids thick along ventral surface and flanks of stem, brown. Tubers absent.

Dioicous. Male plants similar in size to female plants. Antheridia clustered on dorsal surface posteriorly in between leaves; ovoid, 237.5–350 × 225–335 µm. Perigonial scales absent. Archegonia only seen clumped around bases of caulocalyces. Caulocalyces 1 to 6 per shoot, dorsal, campanulate to urceolate, with 1 or 2 sinuses; with the height less than the plant width ( 1.3–2.15 mm high), extending slightly higher than the plant leaves; 1.3–1.6 mm across at the widest point, sessile to shortly stipitate; surface with a number of small crests or scale-like projections on the external surface or with several narrow ribs around the circumference of the caulocalyx; caulocalyx margin irregularly lobed to ragged in appearance, frequently with reddish pigmentation; deeply and irregularly lobed; mouth erect to slightly incurved. Sporophytes emergent, with mature setae 3.2–7.75 mm long. Capsules spheroidal to slightly wider than high, due to being slightly depressed at the apex; 1.0– 1.1 mm in diameter, dark brown (RHS 200A brown group); epidermal cells hyaline; inner capsule wall cells with deep brown, I-type, J-type and U-type thickenings. Spores more or less tetrahedral in equatorial view and spheroidal in polar view, 32.5–45 µm diameter, dark brown, disassociated when mature; distal surface with short thick vermiculate bands and nodules, with 17–24 projections around margin, length of projections varying between populations, 2.5 µm long, 2.5–5.0 µm wide at base; micro-ornamentation of intervening surface with low verrucae or papillae; proximal surface with a pattern of large irregular verrucae and papillae; triradiate ridge more or less distinct; equatorial wing absent. Elaters abundant, elongate, infrequently short, 87.5–200 µm long, 7.5–12.5(–17.5) µm wide, occasionally to frequently branched, (1-) 2- or 3- spiraled, with spirals moderately to loosely coiled; outer wall hyaline, spirals dark reddish brown, with surface smooth. Gemmae lacking.

Etymology. Named for the morphological similarity of the gametophyte to that of Fossombronia intestinalis .

Distribution and habitat. Known only from the type locality, growing in Callitris endlicheri low open forest with scattered emergent Eucalyptus .

Conservation status. This species has not been formally evaluated and is so far only known to occur within Bendick Murrell National Park, where it has been recorded from only one site. According to IUCN criteria (IUCN 2019) it would be listed as “Not Evaluated”.