Australia: Norfolk Island: Mount Pitt Reserve, Filmy Fern Trail, off Selwyn Pine Road, 29°01'S, 167°58'E, 130 m, 3 Dec 1984, H. Streimann 32084A, (holotype: CANB650459).

Within the Radula buccinifera complex Radula anisotoma is most similar to Radula strangulata by virtue of its small, rhomboid lobules whose apex lies close to or over the stem, and its leaf-lobes not interlocking over the dorsal stem surface, such that the stem is visible between leaves in dorsal view, and its habit of growing on rocks in association with waterways, but differs by its oblong leaf-lobes that are caducous, fragmenting into several irregular pieces, its narrower and longer female bract lobes, rhombic to trullate lobules and smaller stature.

[From CANB650459] Forming diffuse patches of small shoots, or mixed with other bryophytes, brown in herbarium; shoot systems monomorphic, irregularly branched, Lejeunea- type branching frequent, with additional pseudodichotomous branching due to production of subfloral innovations below gynoecia; 950–1280 mm wide and up to 20 mm long, branches initially smaller in stature than parent shoot, attaining similar stature to parent shoot after two or three leaf pairs; older shoot sectors denuded of leaf-lobes. Stems 90–150 µm diameter, with cortical cells in a single tier of 15–22 rows; cortical cell walls brown-pigmented; external free cortical cell wall continuously thickened, radial longitudinal cortical walls thin or slightly thickened, inner tangential walls discontinuously thickened; medulla cells in 12–20 rows, cell walls faintly yellow-pigmented or colourless, with small to medium-sized triangular trigones, walls between trigones unthickened. Cortical cells on dorsal stem surface arranged in straight longitudinal rows on young and mature shoot sectors. Leaf insertion not reaching dorsal stem mid-line, leaving one or two dorsal cortical cell rows leaf-free, dorsal leaf-free strip present; leaf insertion not attaining the ventral stem mid-line, leaving two ventral cortical cell rows leaf-free. Leaf lobes oblong-elliptic, 380–710 µm long by 300–490 μm wide, contiguous, not falcate, acroscopic base lying in plane with stem, plane, not interlocking over the dorsal stem surface, stem visible between leaf lobes in dorsal view; margins irregularly repand, marginal cells bulging, the interior lobe margin not or only weakly ampliate, not or hardly riding onto dorsal stem surface, antical margin curved, exterior margin sharply curved through nearly 100°, postical margin straight; angle between postical lobe margin and keel c. 135°. Lobules rhomboid, remote, one tenth to one eighth the lobe area, 140–350 µm long by 105–240 μm wide; keel straight or rarely slightly arched, angle between keel and stem 135°, keel apex and postical lobe margin flush; interior lobule margin free for one third to one half its length, free portion not or weakly ampliate, hardly riding onto ventral stem surface, not concealing the stem in ventral view; acroscopic margin straight or curved; inclined inwards toward the stem; apex acute, laying close to or over the stem margin, free exterior margin straight to weakly curved, margins irregular; lobe-lobule junction level with or slightly postical to the acroscopic end of stem insertion; attached to stem along 0.5–0.33 of the interior margin, stem insertion more or less linear, gently curved at acroscopic and basiscopic ends, not revolute; lobule apex bearing a single papilla, with another two papilla situated on the interior lobule margin above the stem insertion. Leaf lobe cells rounded, not arranged in rows, unequally sized, 9–24 µm long by 9–19 μm wide, thin walled with concave trigones, medial wall thickenings absent; cells of lobe margin smaller than those of leaf middle, quadrate to rectangular, 9–14 µm long and wide, interior and exterior cell walls not differentially thickened; leaf lobe cell surface smooth. Oil-bodies not known. Asexual reproduction by caducous leaf lobes, fragmenting into several irregular pieces, marginal lobe cells often proliferating to form bud-like shoot primordial. Dioicous. Androecia not known. Gynoecia terminal on branch shoots, subtended by 2 or 3 subfloral innovations that are the same size as the branch shoot and are again fertile; archegonia 115–130 µm tall, archegonial neck 6 cell columns; 14–15 per gynoecium on a small disc of tissue, encompassed by the protoperianth; female bracts in one or one and a half pairs, symmetrical, imbricate, narrow oblong-elliptic, lobe 655–975 μm long by 265–450 μm wide, margins entire or repand; lobules rhomboid to trullate, one fifth to one quarter the lobe area, apex obtuse to acute, not or shallowly notched, keel arched, margins irregular; bract insertion lines interlocking dorsally and ventrally, insertion equitant. Perianths c. 3100 µm long and 660 µm wide at mouth, mouth repand, more or less parallel sided for upper third, then tapering to tubular stem perigynium comprising the lower third to half, broadest at mouth, walls 2- or 3-stratose at junction with perigynium, unistratose above. Long stem perigynium present, multi-stratose throughout. Calyptral perigynium present.

From Greek an (αν-): not, isos (ισοσ): even, tomos (τοµος, m.): slice, piece - uneven slice, in reference to the caducous leaf lobes that fragment into uneven pieces.

Radula anisotoma is currently known only from Norfolk Island where, at the only known location, it occurred in dense forest at 130 m within Mt Pitt Reserve. The plants grew beside a creek, presumably within a gully, on a rock admixed with Lejeunea anisophylla Mont., Metzgeria sp. and Radula cf. novae-hollandiae (see comments below under Radula farmeri Pearson for explanation).

Identification of Radula anisotoma should present no difficulty. The most accessible morphological character of Radula anisotoma that differs from all other members of the Radula buccinifera complex is the production of caducous leaves and associated proliferation of marginal lobe cells to form bud-like shoot primordial. Caducous leaves are not produced by any other member of the Radula buccinifera complex, with the exception of Radula mittenii which differs in a number of macro- and micro-morphological characters, and bud-like shoot primordia have only been observed twice, on two different specimens of Radula strangulata (M.A.M. Renner pers. obs.).

Radula anisotoma is most similar to Radula strangulata and, notwithstanding the differences described above, could be confused with that species. However, there are several subtle differences between Radula anisotoma and Radula strangulata in the shape of leaf lobes, lobules, and female bracts, which will aid identification. The leaf lobes of Radula anisotoma are oblong, whereas they are round in Radula strangulata. The lobules of Radula anisotoma are rhombic to trullate, whereas they are rhombic to longitudinally rectangular in Radula strangulata. The female bract lobes are narrowly oblong in Radula anisotoma, whereas they are elliptic-ovate in Radula strangulata. Finally, Radula anisotoma is generally a smaller plant than Radula strangulata. Comparison with known material is recommended in order to appreciate the degree of difference in shape between, as well as variation within, each species when making determinations.

Australia: Norfolk Island: Mount Pitt Reserve, Filmy Fern Trail, off Selwyn Pine Road, 29°1.3'S, 167°57.6'E, 130 m, 3 Dec 1984, H. Streimann 32078 (CANB650457, NICH, NY, EGR, H); ibid. H. Streimann 32083, CANB650458.

Australia: New South Wales: Merrits Creek 3 km east of Mt. Kosciuszko, 1870 m, 9 Feb 1978, H. Streimann 5358A (holotype: NICH, isotype: CANB!).

Forming pure turfs or mats of shoots, dark brown in herbarium; shoot systems regularly pinnately branched, with additional pseudodichotomous branching in female plants due to production of pairs of subfloral innovations below gynoecia; dimorphic, primary shoots 1.5–1.8 mm wide and up to 40 mm long, secondary shoots smaller in stature than parent shoot, 0.8–1.0 mm wide, and either apparently terminating growth after 4 to 7 leaf pairs, or producing reproductive structures and, in female plants, continuing vegetative growth; older shoot sectors retaining leaf-lobes.

Stems 120–160 µm diameter, with cortical cells in a single tier of 23–29 rows, cortical cell walls yellow-brown pigmented, external free cortical cell wall continuously thickened, radial longitudinal cortical walls thin or slightly thickened, inner tangential walls thickened; medulla cells in 23–45 rows, medulla cell walls faintly yellow-pigmented, thin walled, small triangular trigones, medial walls unthickened. Cortical cells on dorsal stem surface arranged in straight longitudinal rows on young and mature shoot sectors. Leaf insertion reaching dorsal stem mid-line, leaving no dorsal cortical cell rows leaf-free; leaf insertion not attaining the ventral stem mid-line, leaving two ventral cortical cell rows leaf-free. Leaf lobes rotund, 475–920 µm long by 400–780 μm wide, contiguous, not falcate, acroscopic base not sharply deflexed away from stem, weakly concave, not or weakly interlocking over the dorsal stem surface, stem visible between leaf lobes in dorsal view; margins entire or crenulated, not repand, the interior lobe margin shallowly ampliate, reaching the opposite stem margin, antical and exterior margins more or less continuously curved, postical margin shallowly curved or straight; angle between postical lobe margin and keel 140–180°. Lobules quadrate on leading shoots, one sixth to one quarter the lobe area, 330-605 µm long by 370–595 μm wide; keel straight to shallowly curved, angle between keel and stem 100–135°, keel turning through up to 30°, keel apex and postical lobe margin flush; interior lobule margin free for one quarter to one third its length, free portion ampliate, extending half way across the ventral stem surface or more; acroscopic margin S-shaped to straight, apical portion slightly inclined toward stem or perpendicular to it; apex obtuse but usually weakly apiculate; free exterior margin straight, margins plane, entire; lobe-lobule junction level with or slightly postical to the acroscopic end of stem insertion; attached to stem along 0.66–0.75 of the interior margin, stem insertion gently curved, not revolute; lobule apex bearing a single papilla, another two papilla situated on the interior lobule margin above the stem insertion. Leaf lobe cells rounded-oblong, not arranged in rows, unequally sized, 13–35 µm long by 11–21 μm wide, thin-walled with small triangular trigones, medial wall thickenings absent; cells of lobe margin smaller than those of leaf middle, quadrate to rectangular, 11–18 µm long by 9–13 µm wide, interior walls moderately and continuously thickened, exterior wall moderately and differentially thickened at mid-wall, forming a conspicuous bulge and imparting a crenulate appearance to lobe margin; leaf lobe cell surface unornamented, smooth. Oil-bodies 2 or 3, light brown, granular, internally homogeneous, filling the cell lumen. Asexual reproduction absent. Dioicous. Androecia on branches that usually terminate after production of 4 or 5 pairs of antheridial bracts, but rarely branches indeterminate, bearing ∞ pairs of antheridial bracts; lobules epistatic, keel deeply curved, bucket-like, free apical portion triangular, apex acute, interior margin ampliate, covering ventral stem surface, and imbricate with adjacent antheridial lobules; lobes rounded, not caducous, antheridia not seen. Gynoecia terminal on branch shoots, subtended by two or three subfloral innovations that are full-sized and again fertile; archegonia 125–150 µm tall, archegonia neck five cell columns, 10 per gynoecium on a small disc of tissue, encompassed by a low protoperianth; female bracts in one pair, symmetrical, tightly imbricate, elliptic-obovate, weakly falcate, lobe 690–770 μm long by 430–535 μm wide, margins crenulate; lobules rectangular, one half to two thirds the lobe area, apex obtuse, keel straight to arched, margins crenulate; bract insertion lines interlocking dorsally and ventrally, insertion equitant. Perianths 4200–4700 µm long and 1050–1200 µm wide at mouth, mouth entire to irregular, parallel sided for upper two thirds, widening to flask shaped, faint bulb in basal third, broadest in middle of this bulb, 1200–1350 µm wide, then tapering to base. Perianth walls unistratose above, with bistratose bands extending up to half way up perianth, increasing in width toward base, becoming confluent, basal perianth walls progressively increasing in thickness, 2–3-stratose. Long stem perigynium present, 5-6 stratose, cell walls heavily thickened and brown-pigmented. Calyptral perigynium present, base of calyptra 2–4 stratose at base, strata progressively lost, unistratose above, unfertilised archegonia elevated on surface of calyptra.

Australian.

Radula australiana occurs on mainland Australia (NSW, ACT, VIC), and in Tasmania and New Zealand, usually well above treeline in alpine or subalpine shrublands, grasslands and tussocklands where it grows in association with seepages and running water over and around exposed bedrock and boulders on alpine bluffs, rock outcrops and rock piles. However, Radula australiana also inhabits rocky open sites within forest habitats, particularly in Australia where high altitude Eucalyptus forest occurs in the alpine zone, and on bluffs associated with watercourses in New Zealand montane beech forest. Radula australiana is primarily a lithophyte on a wide range of sedimentary, metamorphic, and igneous rocks including greywacke and schist in New Zealand, and granite and basalt in Australia. Microsites occupied by Radula australiana are typically sheltered and shaded, such as the back walls of recesses in rock bluffs, crevices, between boulders within ephemeral streambeds. Radula australiana may also occur in bryophyte turfs on soil, usually in the shade of surrounding woody vegetation or rock. It shares all of these habitats with Radula helix, Herzogobryum teres, Nothogymnomitrion erosum, Cheilolejeunea mimosa, and Andreaea spp.

Individuals vary in branching density, New Zealand plants are typically densely branched, and this also occurs in Australia. Openly branched individuals typically have larger shoots and correspondingly larger lobules that produce more pronounced acuminate lobule apices. These differences may be associated with both patch age and microsite. Shoots colonizing naked rock are always openly branched. Those growing in bryophyte turfs on soil are often closely branched.

One of the first clues to the identity comes from the habitat and microhabitat occupied by Radula australiana, as it is one of the few Australasian Radula species that inhabits subalpine and alpine areas, frequently in association with exposed rock. Among alpine species it is one of two having brown pigments, the other being Radula demissa M.A.M.Renner. Despite the considerable morphological disparity between them, three unrelated species have been confused with Radula australiana. Radula aneurismalis is yellow-green or orange-green, has a single botryoidal, light brown oil-body per cell, possesses microphyllous branches, has a distinct narrowly inflated lobule carinal region that extends the length of the keel, produces androecia on short spike-like lateral branches that may be determinate, and the perianths lack a stem perigynium. In contrast Radula australiana is brown-green, has two or three granular, brown oil-bodies per cell, does not produce microphyllous branches, though lateral branches may be smaller in stature than primary shoots, has a broadly inflated carinal region, produces androecia on long branches and on primary axes, and has perianths with a long stem perigynium.

Radula helix is almost as different from Radula australiana as is Radula aneurismalis. Radula helix is yellow-green, has 3–5 smooth, hyaline, oil-bodies per cell, is paroicous, with androecia immediately below gynoecia, and the perianth lacks a stem perigynium. In contrast, Radula australiana is brown-green, has 2–3 granular, brown oil-bodies per cell, is dioicous, and the perianth has a stem-perigynium.

Radula acutiloba is similar in its lobules having an acuminate tip on main shoots, and on this basis Radula australiana was confused with Radula acutiloba in Devos et al. (2011) by the first author of this contribution who followed herbarium determinations. Though sharing similar lobule shapes, and some phenetic similarity, Radula australiana differs from Radula acutiloba in lacking subdiscoidal gemmae on the leaf lobe margin, by its brown-green not yellow-green colour, by the presence of two or three light to tan-brown oil bodies in each leaf lobe cell, lack of secondary thickening on cell walls in the stem medulla, and by its occurrence in subalpine and alpine habitats. In all populations of Radula acutiloba examined, subdiscoidal gemmae have been present on the leaf lobe margin. This feature alone is sufficient to discriminate between these two species.

Two related species, also members of the Radula buccinifera complex, occasionally co-occur with Radula australiana and may be confused with it. In Australia, Radula buccinifera is typically a forest inhabitant, but at some sites in Victoria and Tasmania where forest occurs over and among exposed granite boulders at high altitude, the ecological envelopes of Radula australiana and Radula buccinifera overlap, and they may co-occur. Morphological characters by which Radula australiana may be distinguished from Radula buccinifera are presented in the recognition section for Radula buccinifera.

In New Zealand, Radula demissa is typically a forest inhabitant, but has an alpine ecotype that, although it has not yet been found co-occurring with Radula australiana, occupies similar microhabitats. Morphological characters by which Radula australiana may be distinguished from Radula demissa are presented in the recognition section for Radula demissa. Radula australiana could be confused with Radula strangulata, for differences between these two species see the recognition section of Radula strangulata.

Australia: New South Wales: Southern Tablelands, Mount Kosciuszko National Park, Main Range track to Kosciuszko summit from Charlotte Pass, 36°27'01"S, 148°18'31"E, 1920 m, 26 Feb 2011, M.A.M. Renner 5114 & E.A. Brown, NSW893115; Southern Tablelands, Mount Kosciuszko National Park, Main Range track to Kosciuszko summit from Charlotte Pass, 36°27'01"S, 148°18'31"E, 1920 m, 26 Feb 2011, M.A.M. Renner 5115 & E.A. Brown, NSW893116; Southern Tablelands, Kosciuszko National Park, unnamed hill north of Daners Creek and Pipers Creek junction, 36°22'35"S, 148°27'37"E, 1600 m, 27 Feb 2011, M.A.M. Renner 5127 & E.A. Brown, NSW909241; Southern Tablelands, Kosciuszko National Park, unnamed hill north of Daners Creek and Pipers Creek junction, 36°22'35"S, 148°27'37"E, 1600 m, 27 Feb 2011, M.A.M. Renner 5129 & E.A. Brown, NSW909251; Southern Tablelands, Kosciuszko National Park, unnamed hill north of Daners Creek and Pipers Creek junction, 36°22'18"S, 148°27'34"E, 1720 m, 27 Feb 2011, M.A.M. Renner 5130 & E.A. Brown, NSW909252;

Australian Capital Territory: 36 km SSW of Capital Hill, Canberra, Tower 2.5 km north of Orroral Tracking Station, 35°37'S, 148°59'E, 1340 m, 22 Oct 1987, H. Streimann 38961, HO312250; New South Wales: Southern Tablelands, Kosciuszko National Park, The Rams Head Range, Merrits Spur, 36°29'S, 148°18'E, 1770 m, 13 Jan 2002, J.A. Curnow 5638, CANB636815; J.A. Curnow 5635, CANB636812; Kosciuszko National Park, 7.5 km NE of Mt Kosciuszko, Blue Lake, 36°24'S, 148°19'E, 2020 m, 3 Mar 1991, H. Streimann 47093, CANB9107074; Snowy Mountains, The Rams Head Range, Charlotte Pass, 36°26'S, 148°19'E, 1830 m, 3 Dec 1965, L.G. Adams 1545, CANB162786, CHR265733;

Victoria: Mt McKay, Alpine National Park, 16 km SSE of Mount Beauty, 36°52'S, 147°14'E, 1840 m, 18 Feb 1994, H. Streimann 53505, CANB9403675; H.Streimann 53469a, MEL2300398; Snowfields, Mount Buller, 37°07'S, 146°25'E, 1665 m, 9 March 1953, J.H. Willis s.n., MEL1037780, as Radula physoloba; Mt Buller area, 37 km ESE of Mansfield, 37°09'S, 146°26'E, 1600 m, 30 December 1992, H.Streimann 50758, CANB9219759; Snowfields, Alpine National Park, Cope Creek, 36°54'S, 147°14'E, 1650 m, 5 March 1993, E.A. Brown 93/72 & K.L. McClay, NSW272960; Snowfields, Baw Baw National Park, Alpine Walking Track, c. 100 m north of Mount Erica car park, 37°53'S, 146°21'S, 1100 m, 9 March 1993, E.A. Brown 93/145 & K.L. McClay, NSW273911; Charlotte Pass, Ramshead Range, Snowy Mountains, c. 6, 000 ft, 3 December 1965, L.G. Adams 1545, FH00284638; Snowfields, Mount Buller, summit, 37°08'41"S, 146°25'29"E, 1795 m, 28 Feb 2011, M.A.M. Renner 5133 & E.A. Brown, NSW875860; Snowfields, Mount Buller, summit, 37°08'41"S, 146°25'29"E, 1795 m, 28 Feb 2011, M.A.M. Renner 5135 & E.A. Brown, NSW875862; Snowfields, Mount Buffalo National Park, Slope immediately below carpark at The Horn, 36°46'33"S, 146°45'51"E, 1614 m, 01 Mar 2011, M.A.M. Renner 5142 & E.A. Brown, NSW875928; Snowfields, Mount Buffalo National Park, Mahomets Tomb outcrop, 36°45'12 S, 146°47'41"E, 1570 m, 01 Mar 2011, M.A.M. Renner 5150 & E.A. Brown, NSW875947; Snowfields, Alpine National Park, Mount Loch, summit, 36°57'30"S, 147°09'19"E, 1858 m, 2 Mar 2011, M.A.M. Renner 5162 & E.A. Brown, NSW875951; East Gippsland, Errinundra National Park, Mount Ellery, track to summit from the Ferntree track, 37°23'38"S, 148°46'21"E, 1080 m, 4 Mar 2011, M.A.M. Renner 5204 & E.A. Brown, NSW909259;

Tasmania: Ben Lomond, Hamilton Crags, 42°32'S, 147°41'E, 1460 m, 5 Jan 1992, A. Moscal 22365, HO301803; Mt. Field, Mt. Field East, 42°40'S, 146°39'E, 1155 m, 12 Apr 1992, A. Moscal 23324, HO132882; Mt. Field, Naturalist Peak, 42°60'S, 146°31'E, 1390 m, 10 Mar 1992, A. Moscal 23011, HO525812;

New Zealand: South Island: Nelson, Kahurangi National Park, Cobb Valley, between Cobb Lake and Round Lake, 41°03'23"S, 172°30'08"E, 1150 m, 19 Feb 2012, M.A.M. Renner 6230, NSW895690; Nelson, Kahurangi National Park, Cobb Valley, Round Lake cirque, 41°03'21"S, 172°29'53"E, 1290 m, 19 Feb 2012, M.A.M. Renner 6239, NSW896176; Hawkdon Ecological Region, Arthurs Pass Ecological District, Arthurs Pass, Temple Basin, 42°55'S, 171°35'E, 1440 m, 1 Apr 2001, M.A.M. Renner 01/114, AK280485; Canterbury Land District, Ohau, South Huxley Valley, 44°4'S, 169°42'E, 1200 m, 9 Nov 1996, D. Glenny 6567, CHR559967; Canterbury Land District, Ohau, South Huxley Valley, 44°02'S, 169°46'E, 1530 m, 9 Nov 1996, D. Glenny 6575, CHR559976; South Westland, northern Olivine Range, north of Dragon, 44°9'S, 168°37'E, 1250 m, 14 Feb 1995, D. Glenny 5769b, WELT-H0010890;Otago Land District, Remarkables Range, head of Wye Creek, 45°5'S, 168°50'E, 1760 m, 28 Dec 1998, D. Glenny 7627, CHR529388; East Dome, Garvie Range, 4500 ft, 5 Dec 1981, J. Child, CHR427233; Earnslaw, N ridge, 24 Oct 1973, J. Child, CHR427228; Fiordland, Fiordland National Park, Cozette Burn, 1080 m, 10 Apr 2002, M.A.M. Renner s.n., CHR583911; South Westland, Haast Pass, western slopes of Mount Armstrong above Brewster Hut, 44°05'22"S, 169°24'55"E, 1530 m, 16 Feb 2012, M.A.M. Renner 6142, NSW895444; ibid, 44°05'27"S, 169°24'56"E, 1580 m, 16 Feb 2012, M.A.M. Renner 6148, NSW895456.

Australia: Tasmania: “ Van Diemen’s Land ”. Syntypes: Voyage of HMS Erebus & Terror. J.D. Hooker s.n. 1840, BM, K, FH00284039! L, NY00831294! ex herb Möller S-B25060! ex herb Lehmann S-B25061! S-B25062! YU; “ Van Diemen’s Land ”, Gunn, FH00284037! “ Van Diemen’s Land”, on Sticta glabra, without collector, date or number, FH00284038!

Radula wattsiana Steph. Species Hepaticarum 4: 211. 1910.

Type: Australia: Cambewarra Mountain, 1903, leg. Rev. W.W. Watts, ex herb. Levier No. 4144 in herb. Steph (as Radula plicata). Lectotype (designated by Castle (1963 p. 46): G00264951! isolectotypes: FH! NSW764184!

[from NY00831294 and MEL38047] Forming interwoven mats of shoots, brown in herbarium, shoot systems regularly pinnately branched, with additional pseudodichotomous branching due to production of pairs of subfloral innovations below gynoecia; dimorphic, primary shoots 1.2–1.7 mm wide and up to 40 mm long, secondary shoots smaller in stature and either apparently terminating growth after five to seven leaf pairs, or continuing vegetative growth and attaining similar stature to primary shoots by fourth to sixth pair of leaves; older shoot sectors retaining leaf-lobes.

Stems 130–155 µm diameter, with cortical cells in a single tier of 25–31 rows, medulla cells in 20–35 rows, cortical cell walls yellow-brown pigmented, ventral cortical walls occasionally yellow pigmented, external free cortical cell wall continuously thickened, radial longitudinal cortical walls thin or slightly thickened, inner tangential walls continuously thickened; medulla cell walls faintly yellow-pigmented, with small triangular trigones, walls between trigones lacking thickenings; cortical cells on dorsal stem surface arranged in straight longitudinal rows on young and mature shoot sectors. Leaf insertion variable within single individuals, reaching the dorsal stem mid-line or not, leaving zero to three dorsal cortical cell rows leaf-free, dorsal leaf-free strip usually present; leaf insertion not attaining the ventral stem mid-line, leaving two to five ventral cortical cell rows leaf-free. Leaf lobes rotund-ovate, 600–845 µm long by 400–655 μm wide, contiguous, not to weakly falcate, acroscopic base not sharply deflexed away from stem, plane, not interlocking over the dorsal stem surface, stem visible between leaf lobes in dorsal view; margins irregularly but minutely repand, otherwise entire, the interior lobe margin shallowly ampliate, not or only just reaching the opposite stem margin, antical margin curved, exterior margin sharply curved through nearly 100°, postical margin shallowly curved or straight; angle between postical lobe margin and keel c. 135°. Lobules quadrate to rhombic when small and large, one eighth to one sixth the lobe area, 310–475 µm long by 215–420 μm wide; keel curved in small stature lobules, to straight, to arched in large stature lobules, angle between keel and stem 135°, keel turning through 90° mostly at keel-lobe junction, keel apex and postical lobe margin with shallow notch; interior lobule margin free for one third its length, free portion weakly ampliate small stature lobules to moderately ampliate on large stature lobules, extending at most half way across the ventral stem surface; acroscopic margin S-shaped (typical in situ) to straight (when flattened), apical portion inclined toward stem; apex obtuse to acute; free exterior margin straight to curved, occasionally with a small knee above the lobe-lobule junction; margins plane, entire or shallowly repand; lobe-lobule junction slightly antical to, or level with, the acroscopic end of stem insertion; attached to stem along 0.66 of the interior margin, stem insertion more or less linear, gently curved at acroscopic and basiscopic ends, not revolute; lobule apex bearing a single papilla, with another two papilla situated on the interior lobule margin above the stem insertion. Leaf lobe cells rounded-oblong, not arranged in rows, unequally sized, 10–23 µm long by 11–19 μm wide; thin walled with small triangular trigones, medial wall thickenings absent; cells of lobe margin smaller than those of middle, quadrate to rectangular, 9–15 µm long and wide, interior and exterior cell walls not differential thickened, cell lumen not bulging medially, leaf lobe cell surface unornamented, smooth. Oil-bodies not known. Asexual reproduction absent. Dioicous. Androecia on lateral branches that usually terminate following production of 2–4 pairs of antheridial bracts, occasionally these branches continue vegetative growth; bract lobules epistatic, keel deeply curved, bucket-like, free apical portion triangular, apex obtuse, inner margin ampliate, plane; lobes rounded, not caducous; antheridia 1–2 per bract. Gynoecia terminal on leading shoots, subtended by two subfloral innovations, usually full-sized and again fertile; archegonia 130–155 µm tall, archegonia neck six cell columns, 6–8 per gynoecium, on a small disc of tissue, interspersed with paraphyses of 1–3 moniliform cells capped by a hyaline papilla, not encompassed by a protoperianth. Female bracts in one pair, symmetrical, tightly imbricate, elliptic-obovate, weakly falcate, lobe 725–845 μm long by 390-610 μm wide, margins entire; lobules rectangular, one half the lobe area, apex obtuse to broadly acute, keel arched, margins entire; bract insertion lines interlocking dorsally and ventrally, insertion equitant. Perianths 2670–3650 µm long and 630–930 µm wide at mouth, mouth repand, more or less parallel sided for upper third, then tapering to tubular stem perigynium comprising the lower third to half, faint bulb in basal third, broadest c. one third from mouth where 660–950 µm wide, walls bi- or tri-stratose at junction with perigynium, unistratose above, cell walls with triangular trigones. Long stem perigynium present, 5-6 stratose throughout, cell walls not thickened or brown-pigmented, hyaline, perianth-calyptra junction elevated above female bracts on 9–15 tiers of cells. Calyptral perigynium present, 2–4 stratose at base, unistratose above, unfertilised archegonia elevated on surface of calyptra.

Horn-bearing.

Radula buccinifera is endemic to Australia, where it is widespread throughout Tasmania, and Victoria but more restricted in New South Wales, being confined to the eastern side of the Great Dividing Range and associated escarpments. In Western Australia it is confined to the far south-west. The northern limit of this species has not been identified, currently the northernmost locality is Point Lookout in New England National Park, in association with Nothofagus moorei. Cool temperate rainforests dominated by Nothofagus also occur in south-east Queensland and Radula buccinifera may be be found in these areas.

Casual field observation suggests the elevational range occupied by Radula buccinifera is correlated with latitude. In Tasmania and Victoria Radula buccinifera occurs across a broad elevational range from sea level to 1500 m, encompassing a range of habitat types from lowland to montane forests, including wet sclerophyll forest and cool temperate rainforest, wetlands, and in alpine scrub and within habitats may occupy a range of microsites from twigs, branches, tree trunks and tree bases, exposed tree roots on the forest floor, to rotting logs, exposed soil on forest banks, dripping rocks adjacent waterfalls, and on rocks within stream beds, sometimes under running water.

The ecological range decreases with latitude; the further north, the more restricted to foothills, escarpments, and mountains in association with cool temperate rainforests. This altitudinal contraction is associated with restriction in the diversity of microhabitats occupied, such that at the northern end of its range, where Radula buccinifera occurs at 1000 m or higher, and is always encountered as a lithophyte most frequently on vertical rock faces associated with bluffs and outcrops.

Radula buccinifera is one of three [Radula novae-hollandiae, Radula strangulata, Radula buccinifera] Radula species in south-eastern Australia that may be found growing under running water. On rocks it frequently co-occurs with Radula novae-hollandiae, forming mixed mats. The type specimen of Radula novae-hollandiae comprises such a mixed patch. In north-eastern New South Wales it may co-occur and form mixtures with a number of other Radula species, initially presenting as confusing and exceptionally variable individuals.

Individual populations exhibit generous amplitude in shoot stature and lobule shape. Lobules vary from rhombic-quadrate with little ampliation of the interior margin and a straight antical margin, to quadrate with a pronounced ampliate interior margin and an S-shaped antical margin having a distinct, obtuse, lobule apex. Colour of individuals varies, from glaucous yellow-green to dark green, in part this appears correlated to microhabitat, with epiphytic plants tending yellow green, and lithophytic plants being dark green.

The amplitude of morphological variation expressed between individuals appears negatively correlated with latitude. The greatest morphological variation between individuals in plant colour, shoot size and lobule shape occurs in the southern end of the distribution. Individuals vary from brown-green, mid-green and glaucous green and from small to large, with associated differences in lobule shape. In Central and Northern Coast, and Northern Tableland regions in the northern part of Radula buccinifera range, individuals are fairly consistent in morphology being large, mid-green, and having lobules whose antical margin is more or less straight, with an pronounced ampliate free interior margin.

Recognition. Despite the variability exhibited by Radula buccinifera this species is relatively easy to recognize. The first clue to identity comes from the habitat and microhabitat the plants occupy; Radula buccinifera inhabits forest interiors, frequently in microsites on or close to the forest floor that are often well shaded. Other species of the Radula buccinifera complex with which Radula buccinifera could be confused on morphological grounds almost all occupy quite different habitats and microsites.

Radula australiana inhabits subalpine and alpine habitats typically dominated by shrubland, tussockland or grassland, and is almost always found above tree-line. However, Radula australiana and Radula buccinifera may co-occur in forest interiors on forested mountain tops in Victoria and Tasmania, particularly in association with exposed large granite boulders, for example at Mt. Ellery in Errinundra National Park, Victoria. The most accessible morphological character by which Radula buccinifera differs from Radula australiana is the shape of the leaf lobes, where the junction between the lobe and keel forms a simple angle in Radula buccinifera and the leaves are not or weakly falcate as a result. In Radula australiana the keel runs more or less seamlessly into the lobe outline, the two following the same curve. If this character proves ambiguous, lobule shape is a good source of discriminating characters. Lobule shape should always be assessed on the basis of hydrated, slide-mounted material, and at least 50× magnification. When hydrated the lobules of Radula buccinifera are quadrate to rhombic, and one eighth to one sixth the lobe area. The antical margin is usually (northern plants excepted) S-shaped in situ (straight when flattened), but this is more pronounced with a deep medial curve, and the apex is obtuse. The lobules of Radula australiana are quadrate to rectangular, and one quarter the lobe area. The antical margin is S-shaped in situ and when flattened, but the medial curve is relatively shallow, and the apex varies from obtuse to acute. Further differences exist in the lobe marginal cells that bulge in Radula buccinifera, but are crenulate, due to medial thickening on the external cell wall in Radula australiana. Finally, if all of these characters prove ambiguous, diagnostic differences can be derived by counting the number of rows of dorsal cortical cells that are not crossed by the leaf insertion lines. In Radula buccinifera 0–3 cortical stem cell rows are leaf free, whereasno cell rows are leaf-free in Radula australiana. Obviously multiple counts from a few shoots are required. If none of these characters leads to a satisfactory conclusion, consider the possibility that the material at hand comprises a mixed collection.

Radula buccinifera may be confused with Radula demissa, with which it co-occurs in Victoria and Tasmania where the two species may occupy similar microhabitats. For characters distinguishing these two species, see the recognition section of Radula demissa.

Radula buccinifera could also be confused with Radula strangulata, as the two species occupy similar microhabitats, both have a dorsal leaf-free strip, and are identical in overall appearance. Lobule shape differences are possibly the best, and only, source of discriminating morphological characters. In Radula buccinifera the antical lobule margin is typically straight and perpendicular to the stem and the lobule apex is obtuse at least in large lobules. In contrast the antical margin of Radula strangulata is either inclined toward the stem or arched and the lobule apex is broadly acute in large lobules. Aquatic morphs of Radula strangulata have longitudinally rectangular lobules, whose straight exterior margin runs parallel with the stem and whose interior margin is ampliate over the ventral stem surface. In Radula buccinifera the lobule is trapeziform or quadrate, and not ampliate to the same degree. More substantial characters have not been identified. Some interpretations of morphology would find (and have found) strong evidence for the synonymisation of Radula buccinifera with Radula strangulata from this circumstance. However, here as in other liverwort complexes morphological unity and the existence of morphological continua are immaterial to the phylogenetic structure underpinning the observed morphological diversity, and the existence of populations of both species intermediate in size and shape does not indicate phylogenetic unity (Renner et al. 2013).

The name Radula buccinifera has been applied to specimens belonging to a wide variety of unrelated species from tropical Queensland, even as far north as Moa Island in the Torres Strait (i.e. CANB9500180). However, with the exception of two specimens collected by Pentzke in 1882, one of which is a mixture of elements from at least two locations (see discussion of the type of Radula mittenii), all records of known provenance from tropical Queensland are based on misidentifications. Radula buccinifera can be distinguished from virtually every species in Queensland by 1) the presence of a stem perigynium in the perianth, 2) the production of two subfloral innovations, 3) the absence of secondary cell wall thickening in the stem medulla, 4) the sub-dimorphic shoot systems, 5) the rhombic lobules, 6) the presence of two papillae on the interior lobule margin, 7) the smooth leaf-lobe cell surfaces. Radula buccinifera may be confused with Radula notabilis, and Radula imposita; for distinguishing characters see the recognition section of those species.

Radula buccinifera is among the most widely misunderstood species of Radula, having been confused in herbarium collections with almost every other Radula species in Australia, and several that aren’t. Misidentifications of Radula buccinifera have been the basis for several records of species now excluded from the Australian flora, including Radula physoloba and Radula plicata. Confusion with Radula physoloba seems attributable to R.A. Bastow, all of whose specimens identified as Radula physoloba in MEL ex herb. R.A. Bastow are Radula buccinifera, and confusion with Radula plicata is attributable to Stephani, who misidentified several gatherings by Weymouth and Bastow.

Radula buccinifera was understandably confused with Radula strangulata by Mitten (1855) who cited collections by Colenso, Stephenson, and Lyall from the southern North Island in his treatment for Hooker’s Flora of New Zealand, and this confusion has been perpetuated in various manifestations. Allison and Child (1975) illustrated Radula strangulata as Radula buccinifera, and again in the next figure as Radula levieri Steph. Renner (2005) made a different, and less forgivable, error when he presented a key to New Zealand species that included Radula buccinifera. The plants he referred to were actually Radula demissa M.A.M.Renner, and his error was based on mis-interpretation of type material.

Castle, however, appears to have been hopelessly confused regarding the identity of Radula buccinifera, arbitrarily placing specimens of Radula buccinifera, Radula demissa, and Radula strangulata under the names Radula buccinifera, Radula mittenii, and Radula wattsiana. As an example, the figure illustrating Radula buccinifera in Castle (1967) includes a male shoot of Radula strangulata. Castle maintained that Radula mittenii differed from Radula buccinifera in its more falcate leaf lobes, and the shorter perianths and he may have had Radula demissa in mind in this assessment.

Yamada (1984) synonymised Radula mittenii with Radula buccinifera on the basis of his examination of ‘holotype’ material held in g, and his assertion that the differences observed were environmental. Yamada’s identification of holotype material is incorrect, his interpretation was derived from examination of duplicate material in Geneva and the implications of this are discussed below under Radula mittenii. The synonymisation of Radula mittenii, having a type from tropical Queensland, with Radula buccinifera by Yamada (1984) seems to have encouraged the application of the name Radula buccinifera to a range of specimens from tropical Queensland, to the point where nearly every species occurring in Queensland has, at some point, been identified as Radula buccinifera. Beyond the specimen collected by Pentzke, no populations attributable to Radula buccinifera from tropical Queenslandexists within herbaria, and the species has not been observed during the course of recent fieldwork in the Wet Tropics of Queensland.

So (2005) identified a Hooker collection from Van Diemens Land as the holotype of Radula buccinifera. This is inappropriate as Hooker and Taylor (1844) did not identify a single type collection, the only specimen details given in the protologue were “Van Diemen’s Land”. Collections from “Van Diemen’s Land” by both R. C. Gunn and J. D. Hooker were made prior to 1844 and were studied by Hooker and Taylor for their contribution to Hepaticae Antarcticae, as made clear in the subtitle to Hooker and Taylor’s (1844) publication, and by the presence of duplicates from both collectors in Taylors own herbarium. At least three gatherings may comprise the syntype series, being the more or less pure gatherings made by Gunn and Hooker, and a gathering on Sticta, whose collector has not been recorded. Furthermore, Castle (1967) had attempted to lectotypify Radula buccinifera, though we are unclear about exactly what Castle intended in his lectotypification. Castle’s (1967) lectotypification of Radula buccinifera is somewhat obscured by his own commentary. In the list of specimens examined he states ‘Van Dieman’s Land, the Type (BM K and Y) and Van Dieman’s Land, R.C. Gunn (BM and K)’ [italics ours]. Here Castle appears to identify two groups of specimens, one of which was collected by Gunn and was not identified as the lectotype. But Castle then notes ‘we may assume that those collections which bear the label Van Diemen’s Land are portions of the collection upon which Thomas Taylor based his Jungermannia buccinifera. Several samples of this type, preserved in the herbaria of the British Museum and of Kew Gardens, also include in the label the name Gunn. Gunn presumably made the type collection as his name, as collector, appears in the title of the article in which the original description of Jungermannia buccinifera was published, without data’. Here Castle implies that the Gunn collection should be regarded as the lectotype. All gatherings comprising the syntype series we have seen, being duplicates of both Hooker and Gunn’s collections, and the specimen sine. coll. are unambiguously assignable to Radula buccinifera, so application of the name Radula buccinifera will remain the same regardless of which gathering and which particular specimen the species is lectotypified on. Castle’s lectotypification at best requires narrowing because he did not identify a single specimen as type, and at worst lectotypification requires repeating because it is not quite clear whether Castle identified a single gathering.