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AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
New species and new records of the lichen genus Rhizocarpon
from Tasmania, with a key to the Australian taxa
Patrick M. McCarthy, John A. Elix & Gintaras Kantvilas
Australasian Lichenology 86 (January 2020), 36–61
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AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
36 37
New species and new records of the lichen genus Rhizocarpon
from Tasmania, with a key to the Australian taxa
Patrick M. McCarthy
64 Broadsmith St, Scullin, A.C.T. 2614, Australia
e-mail: pmcc2614@hotmail.com
John A. Elix
Research School of Chemistry, Building 137,
Australian National University, Canberra, A.C.T. 2601, Australia
e-mail: John.Elix@anu.edu.au
Gintaras Kantvilas
Tasmanian Herbarium, PO Box 5058, UTAS LPO, Sandy Bay, Tasmania 7005, Australia
e-mail: Gintaras.Kantvilas@tmag.tas.gov.au
Abstract
Rhizocarpon austroalpinum P.M.McCarthy, Elix & Kantvilas, R. exiguum P.M.McCarthy,
Elix
& Kantvilas and R. torquatum P.M.McCarthy, Elix & Kantvilas are described as new to
science from Tasmania; the rst species also occurs in alpine New South Wales. Rhizocarpon
exiguum is most similar to R. intersitum Arnold; it differs by having a sparse, minutely areolate
thallus lacking lichen substances, very small apothecia with an exceptionally thin excipulum,
a thin hymenium and signicantly smaller and more sparingly septate, dark brown submuri-
form ascospores. The other new taxa are related to the common, pantemperate R. reductum
Th.Fr., but they have substantially larger apothecia, and they are distinguishable from each
other by a suite of differences in thalline and apothecial anatomy and morphology as well as
thallus chemistry and apothecial pigmentation. Detailed descriptions are provided for the
Tasmanian collections of R. intersitum and R. reductum for comparative purposes. Four other
species of Rhizocarpon are reported for the rst time from Tasmania, including R. aff.
lusitanicum (Nyl.) Arnold, a parasite of the lichen Lepra sp. An updated key is provided to the
22 species currently accepted from Australia.
Introduction
Rhizocarpon Ramond ex DC. (Rhizocarpaceae) is a genus of c. 200 crustose, free-living or
lichenicolous species which is most diverse on montane, siliceous rocks and at temperate to
higher latitudes, particularly in the Northern Hemisphere. Free-living taxa have a rimose to
areolate thallus, a usually distinct prothallus, an often diverse thallus chemistry, innate to
supercial, lecideine apothecia, mostly anastomosing and conglutinate paraphysoids, dis-
tinctive 1–8-spored asci and hyaline to greenish black, halonate, ellipsoid ascospores that can
be transversely septate or submuriform to eumuriform (Runemark 1956; Clauzade & Roux
1985; Timdal & Holtan-Hartwig 1988; Feuerer 1991; Ihlen 2004; Fletcher et al. 2009; Gal-
loway 2007; McCarthy & Elix 2014). The asci have a dark amyloid cap in the upper part of the
tholus, a non-amyloid ascus wall, and they lack an ocular chamber (Hafellner 1984; Ihlen
2004; Fletcher et al. 2009).
Recent studies of Australian Rhizocarpon have seen the description of R. austroamphibium
Fryday & Kantvilas from Tasmania (Fryday & Kantvilas 2012), while an assessment of the
genus in mainland Australia recognized 16 species including the newly described R. avo-
medullosum Elix & P.M.McCarthy and R. vigilans P.M.McCarthy & Elix (McCarthy & Elix
2014). Subsequently, R. ridescens (Nyl.) Zahlbr., a Northern Hemisphere species, was reported
from New South Wales (Elix et al. 2019), and another endemic taxon, R. bicolor Elix &
P.M.McCarthy, was described from the Australian Capital Territory, New South Wales and
Victoria (Elix & McCarthy 2019).
In this paper, R. exiguum is described as new from siliceous rock on the west coast of
Tasmania; it is most closely related to R. intersitum Arnold, which has a scattered distribution
in the Northern Hemisphere and in temperate mainland Australia, as well as in Tasmania.
Rhizocarpon austroalpinum and R. torulosum, both broadly similar to the pantemperate R.
reductum Th.Fr., are also described as new, from alpine, siliceous rocks (in Tasmania and New
South Wales) and from a seasonally inundated, lowland river bed, respectively. Morphological
and chemical variation is documented for Tasmanian R. intersitum and R. reductum, four other
Rhizocarpon taxa are reported for the rst time from Tasmania, including the lichenicolous R.
aff. lusitanicum (Nyl.) Arnold, and an updated key is provided to the 22 species currently
known from Australia.
Methods
Observations and measurements of photobiont cells, thalline and apothecial anatomy, asci and
ascospores were made on hand-cut sections mounted in water. Sectioned apothecia were
treated with 10% potassium hydroxide (K), 50% nitric acid (N) and 10% hydrochloric acid
(H). Asci were observed in Lugol’s Iodine (I), with and without pretreatment in K. Chemical
constituents were identied by thin-layer chromatography (Elix 2014) and comparison with
authentic samples.
The species
1. Rhizocarpon austroalpinum P.M.McCarthy, Elix & Kantvilas, sp. nov. Figs 1, 2, 3A, 4A
MycoBank No.: MB 832447
Characterized by the whitish to pale grey areolate thallus that lacks lichen substances and all
visible traces of a prothallus, large, often adnate to subsessile apothecia [(0.43–)0.88(–1.38)
mm diam.] with a thin to moderately thick proper exciple (80–140 µm) producing a deep red
leachate in K, an epihymenium that is N+ pale brown and then decolorized, a thick, dark
hypothecium [(80–)160–350(–450) µm], and hyaline and mostly submuriform ascospores,
(18–)26(–37) × (9–)13(–17) µm, with (6–)7–15(–17) cells in optical section.
Type: Australia. Tasmania, Cradle Mountain Lake St Clair Natl Park, Mt Pillinger, 41°49’S,
146°07’E, 1270 m alt., on alpine dolerite boulders, G. Kantvilas 30/15, 6.i.2015 (holotype –
HO 576724).
Thallus crustose, epilithic, rather effuse to determinate and forming colonies to c. 5 cm wide,
off-white, very pale grey or pale to medium greenish grey, 80–250(–400) µm thick, areolate.
Areoles contiguous or somewhat scattered, dull, smooth, plane to moderately convex or,
occasionally, strongly convex, 0.15–0.8(–1.5) mm wide, rimulose or not, angular (when
contiguous) to somewhat rounded (when scattered); surface dull, smooth to minutely and
irregularly uneven, epruinose. Cortex clearly delimited in thin section, 7–12(–15) µm thick,
paraplectenchymatous, comprising 1 or 2 layers of cells, subtending an amorphous, hyaline
necral layer (8–)15–30(–60) µm thick; cortical cells rounded, 4–6(–8) µm wide, thick-walled,
with a dark greenish brown distal wall, the internal wall hyaline. Algal layer continuous,
(30–)50–100(–120) µm thick, with an uneven lower edge; cells green, chlorococcoid, globose
to ellipsoid, rather thick-walled, 6–13(–18) µm diam.; interstitial mycobiont cells vertically
elongate above, thin-walled, 7–11 × 5–7 µm; lower interstitial cells ± parenchymatous, thin-
walled, 2–4(–5) µm wide. Medulla white, (30–)60–100(–250) µm thick or not apparent when
the lower thallus is heavily impregnated with minute rock fragments and crystals, non-amyloid
(I–), not containing calcium oxalate (H2SO4–); hyphae short-celled, 2–4(–6) µm wide. Pro-
thallus not apparent at the thallus margin or internally between or beneath areoles. Apothecia
numerous, uniformly dull black, lecideine, round or broadly ellipsoid in outline, or rather
angular to irregular due to mutual pressure, usually solitary, occasionally paired or in
proliferating or merging clusters of up to 8; single apothecia (0.43–)0.88(–1.38) mm diam. [n
= 105], innate to adnate or subsessile; margin concolorous with the disc, dull black, (50–)80–
120(–160) µm thick, smooth, entire, prominent, usually persistent, becoming thinner at
maturity and often irregularly cracked and/or exuose; disc plane to slightly or moderately
convex, occasionally strongly convex or undulate, smooth to minutely uneven, epruinose, the
colour unchanged when wetted. Proper excipulum annular, frequently uniformly brown-black
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38 39
to carbonized in thin section and 80–140 µm thick; submature and occasional mature excipula
with the outermost c. 70 µm brown-black and the inner c. 30 µm medium brown, of radiating
elongate hyphae; other excipular sections internally pale to medium greenish brown, of
variously orientated hyphae that radiate and darken towards the surface, the outermost 15–30
µm comprised of rounded, thick-walled, brown-black cells 4–7 µm diam.; hyphae closest to
the hypothecium and hymenium long-celled, parallel, thin-walled and periclinal, 12–20 µm
long; excipular section, K+ with deep red leachate, N+ deep red-brown or dark orange-brown,
H–. Epihymenium medium greenish brown to dark brown, occasionally with concolorous
vertical streaks penetrating the hymenium, (10–)15–25(–30) µm thick, non-amyloid, with or
without a hyaline, amorphous, supraepihymenial layer 7–12 µm thick, K+ pale brown or more
intensely greenish, N+ pale brown and then decolorized, H+ rapidly decolorized or greyish
green to violet-green. Hypothecium dark brown to brown-black, (80–)160–350(–450) µm
thick (the uppermost c. 30 µm slightly paler), not inspersed with granules or oil droplets, K+
with deep red leachate, N+ deep red-brown, no change in H, not or only sparingly subtended
by algae; cells vertically elongate above, ± parenchymatous and ellipsoid below, thick-walled,
4–6 µm wide. Hymenium (90–)100–140(–160) µm thick, hyaline to pale blue-green (above),
not inspersed, I+ blue, KI+ blue, K+ blue-green or K–, N+ pale brown-pink or N–, H–;
subhymenium not distinguishable at maturity. Paraphysoids tightly conglutinate in water,
loosening in K, sparingly to abundantly anastomosing, short-celled and constricted at the septa
above, longer-celled below, 1–2(–2.5) µm thick; apical cells not or scarcely swollen, 2–3(–
3.5) µm wide, medium to dark brown. Asci narrowly to broadly clavate or clavate-cylindrical,
(4–)8-spored, (70–)85–125 × 22–35 µm [n = 25]; ascoplasm non-amyloid. Ascospores hyaline,
submuriform or, less commonly, eumuriform at maturity, with 3–5(–7) transverse divisions,
each transverse loculus with 0–1(–2) vertical or diagonal divisions [with (6–)7–15(–17) cells
in optical section], narrowly ellipsoid to almost oblong or obovoid, straight or slightly bent,
irregularly biseriate or more massed in the ascus, or overlapping-uniseriate below, usually
slightly to markedly constricted at the septa, (18–)26(–37) × (9–)13(–17) µm [n = 158]; spore
wall 1.5–2 µm thick at maturity; perispore 3–5(–6) µm thick; apices rounded (especially the
distal end) to subacute; contents clear. Pycnidia not seen.
Chemistry: No substances detected by TLC.
Etymology: The epithet austroalpinum refers to the Australian (and southern) distribution and
alpine habitats of the new species.
Remarks
A robust and highly distinctive species, R. austroalpinum is characterized by the whitish and
often large thallus areoles, the absence of a prothallus and lichen substances, large, prominent,
uniformly black apothecia, (0.43–)0.88(–1.38) mm diam., with an epihymenium that is N+
pale brown and then decolorized, a carbonized excipulum and an exceptionally thick, brown-
black hypothecium. By contrast, the pantemperate R. reductum, which is common in southern
Australia, including Tasmania, has apothecia that rarely exceed 0.7 mm in diameter, an
epihymenium that is N+ reddish brown or purple-brown, a thinner excipulum and a much
thinner hypothecium (Fryday 2000; Ihlen 2004; Fletcher et al. 2009; and see below).
Rhizocarpon lavatum (Fr.) Haszl., another species with a thallus that lacks lichen substances
and with rather large apothecia, is known from the British Isles, continental Europe, Scan-
dinavia, Svalbard, North America, North Africa, East Asia, New Zealand and Macquarie
Island (Timdal & Holtan-Hartwig 1988; Feuerer 1991; Galloway 2007; Ihlen 2004; Fletcher
et al. 2009). It can be distinguished from R. austroalpinum by its usually brownish thallus with
an obvious prothallus, apothecia with a much thicker proper margin, an exciple that is paler in
section and not carbonized and a thicker hymenium. Moreover, the ascospores are considerably
larger, 30–50 × 12–25 µm, and fully muriform, having (9–)12–21(–28) locules in optical section.
The new species is currently known from siliceous rocks at two localities in alpine
Tasmania, as well as Mt Kosciuszko in New South Wales. The mainland specimen was
misidentied as R. lavatum by McCarthy & Elix (2014), as was the second Tasmanian
collection cited by McCarthy et al. (2017).
ADDITIONAL SPECIMENS EXAMINED
Tasmania: ● Central Highlands, Skullbone Plains, 42°02’S, 146°19’E, 1000 m alt., on silic-
eous boulders in open heathland, G. Kantvilas 136/12, 29.ii.2012 (HO 564811). New South
Wales: ● Mount Kosciuszko Natl Park, 2 km NE of the summit, 36°20’S, 148°16’E, 2150 m
alt., on [siliceous] rock outcrop in herbeld on ridge, H. Streimann 7632 (part), 14.iii.1979
[CANB, H (n.v.)].
2. Rhizocarpon exiguum P.M.McCarthy, Elix & Kantvilas, sp. nov. Figs 5, 6A, B
MycoBank No.: MB 832448
Characterized by the very pale effuse thallus with a nondescript prothallus and small, plane,
scattered areoles that lack lichen substances and have a non-amyloid medulla, exceptionally
small apothecia [(0.19–)0.29(–0.44) mm diam.] with a very thin proper exciple [35–45(–50)
µm], an epihymenium that is K+ deep purple, comparatively small, mostly 8-spored asci,
62–85 × 24–30 µm, and dark brown, sparingly septate, submuriform ascospores, (17–)20(–24)
× (9–)11(–14) µm, with only (3–)4–7(–8) cells in optical section.
Type: Australia. Tasmania, Trial Harbour, 41°56’S, 145°10’E, 2 m alt., in sheltered crevices of
coastal serpentinite rock outcrops, G. Kantvilas 422/14, 19.ix.2014 (holotype – HO 574852).
Thallus crustose, epilithic, effuse, forming colonies to c. 10–15 mm wide, off-white to pale
creamy grey to medium grey, 50–70(–90) µm thick, areolate. Areoles scattered, rounded,
elongate or irregular in shape, plane, 0.1–0.3(–0.4) mm wide, not rimulose; surface dull,
smooth, epruinose. Cortex clearly delimited in thin section, 20–30 µm thick, paraplec-
tenchymatous, subtending a hyaline necral layer 8–15 µm thick which is either uniformly
amorphous or composed of rounded to angular, thin-walled hyaline cells 3–6 µm wide; cortical
cells rounded, 5–7 µm wide, thick-walled, uniformly hyaline or with a greenish brown distal
wall, the inner walls hyaline. Algal layer continuous, 20–30 µm thick, with an uneven lower
edge; cells green, chlorococcoid, globose to ellipsoid, rather thick-walled, 5–12(–14) µm
diam.; interstitial hyphae short-celled, thin-walled, 3–5 µm wide. Medullary layer poorly
delimited, c. 25–30 µm thick, heavily impregnated with minute rock fragments and crystals,
non-amyloid (I–), not containing calcium oxalate (H2SO4–); hyphae short-celled, 3–5 µm
wide. Prothallus not very conspicuous, black, visible at the thallus margin and between
areoles. Apothecia moderately numerous, uniformly dull black, lecideine, round or broadly
ellipsoid in outline, or rather angular and irregular due to pressure from adjacent areoles,
usually solitary, occasionally paired or in proliferating clusters of 3 or 4, (0.19–)0.29(–0.44)
mm diam. [n = 40], innate between areoles to adnate; margin concolorous with the disc, dull
black, 30–50 µm thick, inconspicuous, smooth, entire, persistent but never very prominent,
occasionally becoming excluded at maturity; disc plane to slightly convex, smooth to minutely
uneven, epruinose, the colour unchanged when wetted. Proper excipulum annular, 35–45(–50)
µm thick and brown-black laterally in thin section, with the outermost 1 or 2 layers of cells
rounded, thick-walled, dark brown, slightly to markedly paler within and consisting of loose,
radiating hyphae 2–3 µm thick, K–, N+ deep purple-brown, H–. Epihymenium dark brown to
brown-black, 15–25 µm thick, non-amyloid, K+ deep purple, N+ purple-brown, H+ deep
maroon-brown. Hypothecium dark brown to brown-black, 80–110 µm thick (the upper c. 20
µm slightly paler), not inspersed with granules or oil droplets, K–, N+ pale red-brown, H+
mid-brown, not subtended by algae; cells vertically elongate above, ± parenchymatous and
ellipsoid below, thick-walled, 3–5 µm wide. Hymenium 85–110 µm thick, hyaline or with pale
greenish vertical streaks, not inspersed, I+ blue, KI+ blue, K–, N–, H–; subhymenium not
distinguishable at maturity. Paraphysoids sparingly to abundantly anastomosing, 1–1.5(–2)
µm thick, short-celled and constricted at the septa, or longer-celled below; apical cells not or
only moderately swollen, 2–3.5(–4.5) µm wide, medium to dark brown, tightly conglutinate in
water, loosening slightly in K. Asci narrowly to broadly clavate, (4–)8-spored, 62–85 × 24–30
µm [n = 12]; ascoplasm non-amyloid. Ascospores medium to dark greenish grey or dark
brown at maturity, initially trans-septate, becoming submuriform [with (3–)4–7(–8) cells in
AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
40 41
optical section], broadly ellipsoid to almost oblong or obovoid or rather irregular in shape,
occasionally soleiform, straight or, commonly, slightly bent, irregularly biseriate or more
massed in the ascus, (17–)20(–24) × (9–)11(–14) µm [n = 100], N+ purple-brown; post-mature
ascospores often almost black and collapsing, the septa completely obscured; spore wall 0.8–
1.2 µm thick at maturity; perispore not apparent or to 4–6(–7) µm thick; apices rounded
(especially the distal end) to subacute; contents clear. Pycnidia not seen.
Chemistry: No substances detected by TLC.
Etymology: The epithet exiguum (L.: little, small, poor, meagre) refers to the scant thallus of
the new species and its very small and inconspicuous apothecia.
Remarks
Rhizocarpon exiguum can be recognized by its pale, sparsely areolate thallus, very small
apothecia with a thin excipulum, small asci and small, brown, few-celled ascospores. While
further collections might be expected to expand its known range of thallus chemistry and even
apothecial pigmentation, as indicated by several other Australian taxa such as R. geographicum
(L.) DC., R. intersitum, R. lecanorinum Anders, R. polycarpum (Hepp) Th.Fr. and R. reductum
(McCarthy & Elix 2014), it is the morphology and anatomy of the new species that are likely
to be most reliable distinguishing characters when compared with other greyish Rhizocarpon
species with dark brown submuriform to eumuriform ascospores. Thus, R. disporum (Hepp)
Müll.Arg. has asci that produce a single eumuriform ascospore 50–75 × 20–30 µm (Fletcher
et al. 2009; McCarthy & Elix 2014), while R. geminatum Körb. has mostly bisporous asci, and
the montane-aquatic Tasmanian endemic, R. austroamphibium Fryday & Kantvilas, contains
gyrophoric acid, has a smooth thallus, innate white-margined apothecia, mainly 2–4-spored
asci and anomalous simple paraphyses (Fryday & Kantvilas 2012). It is the highly variable R.
intersitum that most closely resembles the new Tasmanian species (see below). However, that
lichen almost invariably has a robust, areolate thallus, an often dominant prothallus, larger
apothecia and larger and more septate ascospores (Figs 2, 3). In contrast, the distinctive thallus
and diminutive apothecia and ascospores of R. exiguum provide an unambiguous circum-
scription.
Rhizocarpon exiguum is known only from sheltered serpentine rock at the type locality on
the west coast of Tasmania. Ultramac (serpentine) rocks are widely known to support highly
localised endemic vascular plants (van der Endt et al. 2015), not least in Tasmania where many
such species are known and continue to be discovered and described (for example, Viola
serpentinicola; de Salas 2018). However, these rocks are generally poorly colonised by
lichens, and the species encountered hitherto are almost invariably widespread and ubiquitous
saxicolous species. A possible exception is Cladonia praetermissa var. modesta (Ahti & Krog)
Kantvilas & A.W.Archer which, in Tasmania at least, is mostly (but not exclusively) associated
with serpentine-derived soils (Kantvilas 1991). Thus, Rhizocarpon exiguum is signicant in
being the rst locally endemic, serpenticolous lichen to be discovered in Tasmania.
3. Rhizocarpon intersitum Arnold, Verhandl. Zool.-Bot. Ges. Wien 27, 554 (1877) Figs 6C, 7
[Tasmanian specimens] Thallus epilithic, pale to medium or dark grey or brownish grey,
occasionally greenish or pink-tinged, epruinose, (80–)150–300(–500) µm thick, areolate,
determinate, forming colonies to c. 5–10 cm wide. Areoles scattered or contiguous, rounded,
elongate or irregular in shape (when scattered) or angular to irregular (when contiguous),
plane to moderately or strongly convex, sometimes hemispherical to almost subglobose, (0.1–)
0.3–0.8(–1.0) mm wide. Cortex paraplectenchymatous, 15–25(–35) µm thick, subtending an
amorphous, hyaline, necral layer (5–)8–15(–25) µm thick. Algal layer continuous, 40–70(–
100) µm thick; cells green, chlorococcoid, globose to ellipsoid, rather thick-walled, 5–12(–14)
µm diam. Medullary layer (50–)100–250(–300) µm thick, I–, not containing calcium oxalate
(H2SO4–). Prothallus inconspicuous to, usually, dominant at the thallus margin and between
areoles, dull black, either thin and mbriate or commonly rimose to areolate internally and up
to 0.3 mm thick. Apothecia dull black, lecideine, round or broadly ellipsoid in outline, or
rather angular and irregular due to pressure from adjacent areoles or apothecia, (0.27–)0.66(–
1.08) mm diam. [n = 376], usually solitary, occasionally paired or in small proliferating
clusters, innate between areoles to adnate; disc slightly concave to plane or slightly to
moderately convex, epruinose; margin concolorous with the disc, dull black, 70–120 µm
thick, smooth, entire, persistent but never very prominent, occasionally becoming excluded.
Proper excipulum annular, 60–110(–140) µm thick in section, the outermost 25–40 µm brown-
black, slightly paler within and consisting of loose, radiating hyphae 3–5(–7) µm thick, K+
orange-red, red, purple or deep red-brown, N+ purple, purple-brown or deep orange, H– or H+
deep red-brown. Epihymenium dark brown to brown-black, 10–20(–25) µm thick, K– or
becoming decolourized or K+ weak purple or K+ deep purple, N+ deep red or purple, H– or
H+ deep purple-brown. Hypothecium dark brown to brown-black, (80–)150–200(–250) µm
thick, not inspersed with granules or oil globules, K– or K+ deep red-brown with red-brown
solution, N+ deep red to red-brown, H– or H+ deep red-brown, not subtended by algae.
Hymenium (85–)100–140(–160) µm thick, hyaline or with pale greenish or brown streaks, not
inspersed, I+ blue, KI+ blue, K–, N+ pale red (streaks only), H– or H+ brown. Paraphysoids
sparingly to abundantly anastomosing, 1–1.5(–2) µm thick; apical cells not or moderately
swollen, 2–3.5(–4.5) µm wide, medium to dark brown or blackish. Asci narrowly to broadly
clavate, (4–)8-spored, 85–140 × 27–40 µm [n = 35]. Ascospores medium to dark greenish grey
or dark brown at maturity, submuriform to eumuriform [with (7–)9–15(–17) cells in optical
section], narrowly to broadly ellipsoid to almost oblong or rather irregular in shape, straight or
slightly bent, irregularly biseriate or more massed in the ascus, (22–)29(–38) × (10–)15(–19)
µm [n = 162], N+ red-brown, purple-brown or purple-red; post-mature ascospores often
almost black and collapsing; perispore not apparent or to 4–6(–7) µm thick. Pycnidia not seen.
Chemistry: Rhizocarpon intersitum exhibits diverse thallus chemistry, producing stictic acid
or lacking lichen substances in the Northern Hemisphere (Timdal & Holtan-Hartwig 1988;
Fryday 2010), while the numerous collections from mainland Australia invariably contain
gyrophoric acid (McCarthy & Elix 2014). Tasmanian material includes ve chemotypes by
TLC, as follows: gyrophoric acid chemotype; barbatic acid chemotype [without or with
4-O-demethylbarbatic acid (minor)]; psoromic acid chemotype [with barbatic acid (minor)];
norstictic acid chemotype; and populations without lichen substances. The norstictic acid
chemotype of R. intersitum in Tasmania is rather similar to R. purpurascens Fryday from the
Kerguelen Islands, Campbell Island and southern New Zealand (Fryday 2004), although that
species is somewhat variable in morphology, secondary chemistry and apothecial pigmentation.
Remarks
Supercially, R. intersitum is rather similar to the northern-temperate to boreal R. grande
(Flörke ex Flotow) Arnold, but the latter usually has an I+ blue medulla, and somewhat larger
ascospores. Indeed, while the reliability of thallus chemistry in Rhizocarpon is limited due to
its often almost unparalleled variability, and apothecial pigments are not always informative,
the amyloid reaction of the thallus medulla remains a very useful species level determinant.
Feuerer (1991) included R. intersitum and R. grande in the synonymy of R. eupetraeum (Nyl.)
Arnold, another species with an amyloid medulla.
Rhizocarpon intersitum occurs on exposed, montane siliceous rocks in the Australian
Capital Territory, southern New South Wales, Victoria and Western Australia (McCarthy &
Elix 2014); it was subsequently conrmed from Tasmania by McCarthy et al. (2017). Whereas
many crustose, saxicolous lichens in Tasmania show a preference for either the highly
siliceous, pre-Carboniferous rock types of the western half of the island, or the more recent
and more fertile rocks, such as Jurassic dolerite, of central and eastern parts, the many
collections of R. intersitum suggest that it occurs equally on all major rock types. Nor is any
correlation evident between rock type and chemical composition. Elsewhere in the world, this
species is known from south-western and north-eastern U.S.A., Scotland, Scandinavia and
Central Europe (Clauzade & Roux 1985; Timdal & Holtan-Hartwig 1988; Feuerer 1991 [in
synonymy with R. eupetraeum]; Fryday 2010).
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42 43
TASMANIAN SPECIMENS EXAMINED
Tasmania: ● Mt Arrowsmith, Franklin-Gordon Wild Rivers Natl Park, 42°13’S, 146°04’E,
960 m alt., on [siliceous] rock, G.C. Bratt 1779 & J.A. Cashin, 14.xi.1964 (HO) [barbatic acid
(major)]; ● Flat Bluff, 42°10’S, 145°48’E, 1100 m alt., on [siliceous] rock outcrops in alpine
heathland, G. Kantvilas 99/94, 26.i.1994 (HO) [psoromic acid (major), barbatic acid (minor)];
● track to Clear Hill, 42°41’S, 146°16’E, 1030 m alt., on horizontal surfaces of conglomerate
boulders in a dry, sheltered overhang in buttongrass moorland, G. Kantvilas 28/00, 12.i.2000
(HO) [no lichen substances detected]; ● Loyetea Peak, 41°19’S, 145°57’E, 650 m alt., on
conglomerate boulders, G. Kantvilas 1135/01, 19.xi.2001 (HO) [gyrophoric acid (major)]; ●
Crater Peak, Cradle Mountain Lake Saint Clair Natl Park, 41°40’S, 145°56’E, 1270 m alt., on
Precambrian metamorphosed alpine rocks, G. Kantvilas 570/02 (part), 12.x.2002 (HO)
[norstictic acid (major), connorstictic acid (trace)]; ● Tanina Bluff, 42°39’S, 147°02’E, 890 m
alt., on dolerite boulders in open eucalypt forest, G. Kantvilas 206/05, 24.vii.2005 (HO) [gyro-
phoric acid (major)]; ● Meredith Range, c. 3.5 km SE of Mt Meredith, 41°35’S, 145°17’E,
750 m alt., on granite outcrops in buttongrass moorland, G. Kantvilas 56/11, 2.ii.2011 (HO)
[no lichen substances detected]; ● NE slopes of Mt Bowes, Southwest Natl Park, 42°51’S,
146°25’E, 700 m alt., on quartzite boulders in buttongrass moorland, G. Kantvilas 26/13,
7.iv.2013 (HO) [barbatic acid (major)]; ● Gowan Brae, E side of Nive River, 42°02’S,
146°25’E, 810 m alt., on low basalt outcrop in heathland, G. Kantvilas 128/14, 19.ii.2014
(HO) [norstictic acid (major)]; ● Crocodile Rock, Mt Wellington, 42°53’S, 147°15’E, 725 m
alt., on sandstone bluff in open eucalypt forest, G. Kantvilas 322/14, 17.viii.2014 (HO)
[barbatic acid (major)]; ● North East Ridge, Mt Anne, Southwest Natl Park, 42°55’57.3”S,
146°26’25.6”E, 1090 m alt., on quartzitic rock outcrops in alpine heathland, G. Kantvilas
90/16, 5.ii.2016 (HO) [barbatic acid (major), 4-O-demethylbarbatic acid (minor)]; ● Mt
Hobbs summit, 42°30’S, 147°35’E, 820 m alt., on sheltered dry dolerite boulders, G. Kantvilas
58/18, 10.v.2018 (HO) [gyrophoric acid (major)].
4. Rhizocarpon reductum Th.Fr., Lichenogr. Scand. 2, 633 (1874) Figs 3C, 8, Table 1
[Tasmanian specimens] Thallus pale grey or pale greenish grey to medium or darker grey or
greyish brown, epruinose, sparingly areolate on a mbriate prothallus to contiguous-areolate,
or areolate near the thallus margin and rather robustly bullate-areolate internally, (50–)100–
200(–300) µm thick; areoles usually plane to moderately convex, 0.1–0.4 mm diam. Cortex
usually clearly delimited in thin section, 8–15 µm thick, medium to dark greenish brown,
subtending a hyaline, amorphous layer (5–)10–25(–40) µm thick. Algal layer usually continu-
ous, 50–100(–150) µm thick; cells mostly globose, chlorococcoid, 6–15 µm diam. Medulla
white, (50–)80–150(–200) µm thick, non-amyloid (I–). Prothallus greyish black to black,
broad and marginal or inconspicuous to dominant between scattered areoles, or not apparent.
Apothecia dull greenish or brownish black to jet-black, lecideine, round or broadly ellipsoid in
outline, or rather angular to irregular due to mutual pressure, (0.19–)0.45(–0.77) mm diam. [n
= 923], solitary, or occasionally paired or in proliferating clusters of up to 5, innate between
areoles or subadnate to adnate; margin entire, persistent, concolorous with or slightly paler
than the disc, often with a very thin but distinct whitish inner edge to the margin; disc at rst
shallowly concave to plane, remaining plane or becoming moderately convex or undulate,
epruinose. Proper excipulum annular, uniformly medium to dark brown, or dark olive-brown
to blackish at the outer edge and composed of ± globose cells, internally pale to medium
brown and composed of rather loose to contiguous, radiating hyphae, 30–65(–100) µm thick,
K+ blue-green or greenish brown, N+ purple-brown to deep red or purple. Epihymenium
medium to dark brown or dark olive-green, 10–15(–20) µm thick, K+ blue-green to olive-
green, N+ reddish brown or purple-brown. Hypothecium dark brown to brownish black, (30–)
70–100(–150) µm thick, K+ deep red-brown, N+ dark red or deep red-brown. Hymenium
80–120(–160) µm thick, hyaline, amyloid, not inspersed. Paraphysoids tightly conglutinate,
anastomosing, 1–2(–3) µm thick; apical cells not or slightly swollen, 2–4(–4.5) µm wide,
hyaline to dark brown. Asci narrowly to broadly clavate or clavate-cylindrical, (4–)8-spored,
65–110 × 17–27 µm. Ascospores hyaline, submuriform at maturity, with 5–14(–17) cells in
optical section, (16–)25(–35) × (8–)13(–16) µm [n = 182]; perispore 2–5 µm thick. Pycnidia
not seen.
Chemistry: This species has been reported to contain stictic acid or, very rarely, lacking lichen
substances (Timdal & Holtan-Hartwig 1988; Fryday 2000; Feuerer & Timdal 2004; Galloway
2007; Fletcher et al. 2009; Wang et al. 2015), or containing stictic and norstictic acids (Fryday
2000; Feuerer & Timdal 2004; Fletcher et al. 2009). The most common chemotype in mainland
Australia contains both hypostictic and stictic acids as major substances along with associated
constictic, cryptostictic, menegazziaic and/or peristictic acids (McCarthy & Elix 2014).
Additional chemotypes with gyrophoric and bourgeanic acids, or bourgeanic acid alone, were
also seen. The stictic acid chemotype is dominant in Tasmania, while others produce bourgeanic
acid, gyrophoric acid, psoromic acid, barbatic acid in addition to stictic acid, or lack lichen
substances. In contrast to mainland populations of R. reductum, hypostictic acid is very rare
among Tasmanian collections and is never seen in major quantities (Table 1).
Remarks
Rhizocarpon reductum is the most common species in a rather discrete group of 14 morpho-
logically similar taxa worldwide, all having a greyish, greyish green or brownish, usually
areolate thallus with a non-amyloid medulla and containing a broad suite of lichen compounds.
Asci are predominantly 8-spored, and the ascospores are colourless, submuriform to eumuri-
form and mostly in the range 20–50 µm long (Feuerer 1991; Fryday 2000, 2019; Ihlen &
Fryday 2002, 2004; Ihlen 2004; Galloway 2007; Fletcher et al. 2009; Matwiejuk 2012; Wang
et al. 2015). A common, pantemperate species on siliceous rocks in both hemispheres, it is
known from Western Australia, South Australia, Queensland, New South Wales, the Australian
Capital Territory, Victoria and Tasmania (McCarthy & Elix 2014). It also occurs in the British
Isles, continental Europe, Arctic Eurasia, Morocco, Tunisia, Turkey, the Ukraine, Central Asia,
China, South Africa, North America, Venezuela, Bolivia, Chile, Argentina, the Falkland
Islands, Antarctica and New Zealand (Feuerer 1991 [as R. obscuratum]; Timdal & Holtan-
Hartwig 1988 [as R. obscuratum]; Fryday 2000, 2019; Øvstedal & Lewis Smith 2001 [as R.
obscuratum]; Calvelo & Liberatore 2002; Feuerer & Timdal 2004 [as R. obscuratum]; Gallo-
way 2007; Fletcher et al. 2009; Wang et al. 2015). In Tasmania, R. reductum displays a very
broad ecological amplitude, ranging from littoral to alpine elevations, and from seasonally
inundated rocks in rivers to semi-shaded habitats in open, dry sclerophyll woodlands or at the
margins of closed, wet forest, to highly exposed sites in heathland and moorland. Furthermore,
it has been recorded from all major Tasmanian rock-types with the exception of limestone.
TASMANIAN SPECIMENS EXAMINED
Tasmania: ● behind Bedlam Walls, 42°50’S, 147°20’E, on siliceous rock, M.L. Westbrook,
17.vii.1971 (HO); ● quarry W of Gunns Plains, 41°17’S, 146°03’E, on siliceous rock, G.C.
Bratt 75/387 & J.A. Cashin, 27.i.1975 (HO); ● Cramps Road, Upper Scamander area, 41°24’S,
148°13’E, on mudstone in the open, G.C. Bratt 75/490 & K.M. Mackay, 24.iii.1975 (HO); ●
Huon River at Scotts Peak Road, 42°52’S, 146°22’E, 400 m alt., on serpentine rocks on river
bank, G. Kantvilas 593/81 & P.W. James, 11.viii.1981 (HO); ● Prosser River, Orford, 42°34’S,
147°52’E, 20 m alt., on dolerite rocks in Eucalyptus globulus forest, G. Kantvilas 944/81A,
12.ix.1981 (HO); ● Cassiterite Creek, 2.5 km NW of Balfour, 41°14’S, 144°52’E, 190 m alt.,
on low sill outcrop, A. Moscal 5123, 21.xii.1983 (HO); ● Adams River, 42°43’S, 146°18’E, c.
350 m alt., on siliceous rocks in river bed subject to seasonal inundation, G. Kantvilas 1/00,
12.i.2000 (HO); ● track to Clear Hill, 42°41’S, 146°17’E, c. 750 m alt., on sheltered faces and
crevices of conglomerate boulders in buttongrass moorland, G. Kantvilas 16/00, 12.i.2000
(HO); ● Lady Bay, 43°24’S, 147°01’E, c. 3 m alt., on seashore dolerite in moist sheltered
crevices, G. Kantvilas 313/00, 14.vi.2000 (HO); ● Channel Highway, c. 2 km NE of Ninepin
Point, 43°17’S, 147°11’E, 3 m alt., on coastal sandstone, G. Kantvilas 790/01, 1.ix.2001 (HO);
● Mt Clark, 43°06’S, 147°47’E, 460 m alt., on dolerite outcrops, G. Kantvilas 1358/01,
27.xii.2001 (HO); ● plateau above Lake Skinner, 42°56’S, 146°41’E, 1130 m alt., on alpine
dolerite, G. Kantvilas 170/02, 7.iv.2002 (HO); ● Crater Peak, Cradle Mountain Lake St Clair
Natl Park, 41°40’S, 145°56’E, 1270 m alt., on Precambrian metamorphosed alpine rock, G.
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44 45
Kantvilas 570/02, 12.x.2002 (HO); ● junction of Holly Road and Gordon River Road, 42°48’S,
146°05’E, 320 m alt., on quartz pebbles along roadside in wet scrub, G. Kantvilas 605/02,
11.xii.2002 (HO); ● near Blythe River, 41°14’S, 145°56’E, 250 m alt., on weathered basalt
along roadside in pasture, G. Kantvilas 519/03, 12.x.2003 (HO); ● Western Explorer Road, c.
42 km S of Rebecca Road turnoff, 41°25’S, 145°03’E, 400 m alt., on quartzite outcrop in
buttongrass moorland, G. Kantvilas 610/03, 14.x.2003 (HO); ● near summit, South Sister,
41°32’S, 148°10’E, 800 m alt., on exposed dolerite boulders, G. Kantvilas 416/04, 10.xi.2004
(HO); ● Daley property, ‘High Country’, c. 2 km W of Long Point, 42°20’S, 147°48’E, 305 m
alt., on dolerite boulders in open Eucalyptus pulchella woodland, G. Kantvilas 8/06, 1.i.2006
(HO); ● Lake Highway, near Projection Bluff, 41°44’S, 146°43’E, 1100 m alt., on dolerite
boulder along roadside at edge of rainforest, G. Kantvilas 318/12, 5.vii.2012 (HO); ● Cherry
Tree Hill, along O-Road, 41°58’S, 148°08’E, 180 m alt., on dolerite boulders in dry sclerophyll
forest, G. Kantvilas 325/12, 25.vii.2012 (HO); ● Espies Craig, 42°34’S, 147°01’E, 600 m alt.,
on vertical dolerite tor in open eucalypt forest, G. Kantvilas 363/12, 14.viii.2012 (HO); ● N
summit of Mt Rogoona, Walls of Jerusalem Natl Park, 41°53’S, 146°12’E, 1330 m alt., on
alpine dolerite, G. Kantvilas 669/12, 27.xi.2012 (HO); ● Skullbone Plains, c. 200 m from road
intersection to Nive River, 42°02’S, 146°21’E, 970 m alt., on alpine dolerite, G. Kantvilas
726/12, 12.xii.2012 (HO); ● Windy Moor, track to Mt Field East, Mount Field Natl Park,
42°40’S, 146°38’E, 1170 m alt., on dolerite at interface of alpine heathland and woodland, G.
Kantvilas 16/13, 17.iii.2013 (HO); ● NW of settlement, Granville Harbour, 41°48’S, 145°02’E,
3 m alt., on coastal basalt, G. Kantvilas 87/13, 16.v.2013 (HO); ● Interview River, just up-
stream from mouth, Arthur-Pieman Conservation Area, 41°35’S, 144°53’E, 3 m alt., on granite
boulders semi-submerged in fresh running water, G. Kantvilas 150/15, 31.i.2015 (HO); ●
summit of knoll c. 0.5 km NE of Wielangta Hill, 42°40’S, 147°51’E, 550 m alt., on dolerite
boulders in open eucalypt forest, G. Kantvilas 147/16, 2.vii.2016 (HO); ● Crest Range,
Southwest Natl Park, 43°17’31”S, 146°30’26”E, 960 m alt., on alpine, metamorphosed
mudstone outcrops, G. Kantvilas 202/16, 4.ii.2016 (HO); ● NE summit, Mt Anne, at the W rim
of the Annakananda Sinkhole, Southwest Natl Park, 42°55’57”S, 146°26’29”E, 1050 m alt.,
on sheltered, alpine, siliceous outcrops, G. Kantvilas 93/16, 4.ii.2016 (HO); ● summit, Three
Thumbs, 42°36’S, 147°52’E, 545 m alt., on dolerite, G. Kantvilas 234/16, 25.ix.2016 (HO); ●
Lime Bay Nature Reserve, c. 1 km N of Plunkett Point, 42°59’S, 147°43’E, 2 m alt., on littoral
sandstone boulders, G. Kantvilas 251/16, 15.x.2016 (HO); ● Rapid River, near bridge on the
Tarkine Drive, 41°09’S, 145°06’E, 70 m alt., on siliceous rocks along river bank in rainforest,
G. Kantvilas 376/16, 26.x.2016 (HO); ● Tasman Bay, 42°51’S, 147°55’E, 2 m alt., on sheltered
side of seashore dolerite boulder, G. Kantvilas 406/16, 27.xii.2016 (HO); ● Russell River, at
bridge on the Russell Road, 42°57’S, 146°47’E, 130 m alt., on siliceous rocks along river bank
(probably occasionally inundated), G. Kantvilas 30/17, 3.i.2017 (HO); ● summit of Mt Pon-
sonby, 42°27’S, 147°32’E, 810 m alt., in sheltered overhang among dolerite boulders, G.
Kantvilas 117/17, 17.vi.2017 (HO); ● Windsong property, NW corner adjacent to Swanston
Road, 42°21’S, 147°54’E, 60 m alt., on dolerite boulders and exposed bedrock in a paddock,
G. Kantvilas 173/17, 26.x.2017 (HO); ● Saw Back Range Track, c. 0.5 km SE of Welcome
Rock, 42°47’S, 146°21’E, 600 m alt., on siliceous pebbles in an abandoned road through
buttongrass moorland, G. Kantvilas 92/18, 2.ix.2018 (HO).
5. Rhizocarpon torquatum P.M.McCarthy, Elix & Kantvilas, sp. nov. Figs 3B, 4B, 9
MycoBank No.: MB 832449
Characterized by the pale and rather thick, smooth, areolate thallus with hypostictic acid
(major) and a distinct marginal prothallus, large, adnate to subsessile apothecia [(0.52–)0.86
(–1.30) mm diam.] with a thick margin [80–160(–200) µm thick] that can be concolorous with
the blackish disc, or moderately to considerably paler, then often retaining a whitish inner
collar, not releasing a deep red leachate in K, a pale epihymenium that is K+ pale pink and N+
pale red-brown, a thick hypothecium [170–300(–380) µm] and mostly submuriform asco-
spores, (22–)28(–35) × (10–)13(–17) µm, with (5–)7–15(–18) cells in optical section.
Type: Australia. Tasmania, Frankland River, at bridge on Blackwater Road, 41°11’S, 144°52’E,
80 m alt., on seasonally inundated, siliceous rocks in river bed, G. Kantvilas 464/15, 10.xi.2015
(holotype –HO 581537).
Thallus crustose, epilithic, determinate, forming colonies c. 1–4 cm wide, greyish white, or
pale grey with a greenish tint, or patchily medium grey, (60–)100–200(–300) µm thick, rimose
to areolate. Areoles contiguous, dull, smooth to minutely or coarsely rugulose, epruinose,
mostly plane to very slightly convex, 0.2–1(–1.2) mm wide, angular, irregular. Cortex absent,
the thallus with an uppermost, hyaline, amorphous, necral layer 4–7(–10) µm thick, this sub-
tended directly by massed algal cells or by an alga-free, paraplectenchymatous layer, 20–25
µm thick, of thin-walled, hyaline cells 5–8 µm wide. Algal layer discontinuous or continuous,
70–150(–200) µm thick, with an even upper edge and an uneven lower edge; cells green,
chlorococcoid, globose to ellipsoid, rather thick-walled, 6–12(–16) µm diam.; interstitial
mycobiont cells vertically elongate above, thin-walled, 4–8 µm wide; lower interstitial cells ±
parenchymatous, thin-walled, 3–5 µm wide. Medulla white, 30–60(–80) µm thick or thinner
and poorly dened when the lower thallus is heavily impregnated with minute rock fragments
and crystals, non-amyloid (I–), not containing calcium oxalate (H2SO4–); hyphae short-celled,
2–5 µm wide. Prothallus well-dened, dark grey to black, marginal, less commonly internal
between areoles. Apothecia numerous, dull greenish black to black, lecideine, mostly round,
occasionally broadly ellipsoid in outline or rather irregular due to mutual pressure, usually
solitary, occasionally paired or in proliferating or merging clusters of up to 4, (0.52–)0.86
(–1.30) mm diam. [n = 80], initially innate, later adnate to subsessile; margin to 200 µm thick
when immature, entire, the inner half whitish in surface view, the outer half greenish black, at
maturity dull black and concolorous with the disc or somewhat to considerably paler, or
retaining a whitish inner collar, 80–160(–200) µm thick, smooth, entire, scarcely prominent
above the surface of the disc, but usually persistent; disc plane to slightly or moderately
convex, occasionally strongly convex, minutely to coarsely uneven, epruinose, the blackish
colour scarcely changing when wetted. Proper excipulum annular, often becoming uniformly
brown-black (thin section) and 100–140(–160) µm thick; immature, submature and many
mature excipula with the outermost c. 15–40 µm pigmented dark brown to brown-black, of
rounded, thick-walled cells, internally pale brown and composed of loose, elongate, radiating
hyphae with cells 5–8(–10) × 3–5 µm; the excipular tissue closest to the hymenium ± hyaline,
of hyphae 2–3 µm wide in a loose reticulum; excipular section K+ mid-brown, N+ deep red-
brown, H+ mid-brown. Epihymenium scarcely delimited from the hymenium, or pale to dark
brown and 10–20 µm thick, occasionally with concolorous, vertical or diagonal streaks to 15
µm wide penetrating the hymenium or forming a distinctive reticulum down to the hypo-
thecium, non-amyloid, K+ pale pink, N+ pale red-brown, H–. Hypothecium dark brown to
brown-black, 170–300(–380) µm thick (the upper c. 20–30 µm slightly paler), not inspersed
with granules or oil droplets, K+ with yellowish leachate, N+ deep red-brown, H+ mid-brown,
not subtended by algae; cells rather elongate above, ± parenchymatous and ellipsoid below,
thick-walled, 2–3(–4) µm wide. Hymenium 110–190 µm thick, hyaline to pale brown or pale
greenish brown, not inspersed, I+ blue, KI+ blue, K+ faint pink, N–, H–; subhymenium not
distinguishable at maturity. Paraphysoids tightly conglutinate in water, loosening in K,
sparingly to abundantly anastomosing, short-celled, not or scarcely constricted at the septa,
1.5–2(–2.5) µm thick; apical cells not or scarcely swollen (to 3 µm wide), hyaline to pale
brown. Asci narrowly to broadly clavate or clavate-cylindrical, (4–)8-spored, 105–140 × 21–
32 µm [n = 15]; ascoplasm non-amyloid. Ascospores hyaline, mostly submuriform, occasion-
ally eumuriform at maturity, with 3–5(–7) transverse divisions, each transverse loculus with
0–1(–2) vertical or diagonal divisions [with (5–)7–15(–18) cells in optical section], narrowly
ellipsoid to oblong-ellipsoid, obclavate or oblong, occasionally almost soleiform, straight or
slightly bent, irregularly biseriate or more massed in the ascus, usually slightly constricted at
the septa (particularly the primary septum), (22–)28(–35) × (10–)13(–17) µm [n = 85]; spore
wall 1–1.5(–2) µm thick at maturity; perispore 4–5(–6) µm thick; apices mostly rounded
(especially the distal end); contents clear. Pycnidia not seen.
Chemistry: Hypostictic acid (major) and hyposalazinic acid (trace) by TLC.
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46 47
Etymology: From the Latin torquatus (adorned with a collar), in reference to the immature and
many mature apothecia having a distinct, whitish ring at the inner edge of the margin.
Remarks
Rhizocarpon torquatum is characterized and distinguished from similar species by attributes
of thallus morphology and chemistry as well as apothecial anatomy and pigmentation. Thus,
while the newly described R. austroalpinum (above) has similarly large apothecia and shares
moderately large ascospores, its thallus lacks lichen substances, nor is it bounded by a visible
prothallus, the thinner proper exciple is considerably darker inside and out, and it leaches a red
solution in K. The apothecia of R. torquatum are comparable in size to those of R. lavatum, but
the latter has fully muriform ascospores, 30–50 × 12–25 µm, and with (9–)12–21(–28) cells in
optical section. Finally, the common R. reductum is most readily separated by its unequivocally
smaller apothecia, which are (0.19–)0.28–0.62(–0.77) mm diam. in Tasmania.
A seemingly reliable diagnostic character in the type specimen of R. torquatum is the
absence of the parenchymatous cortex that is almost invariably seen in species of Rhizocarpon.
Instead, the thallus has only a thin, uppermost necral layer. By contrast, most Tasmanian
specimens of R. reductum (and indeed both collections of R. austroalpinum) have a clearly
delimited parenchymatous cortex of rounded, brownish, thick-walled cells. The single
exception among the specimens of the former taxon examined (G. Kantvilas 1/00) occurred on
siliceous rocks in river bed subject to seasonal inundation, suggesting the development of a
cortex might be heavily inuenced by environment and, specically, its moisture regime.
The new species is known only from the type locality, viz. seasonally inundated, siliceous
rocks in the Frankland River in north-western Tasmania, where the river runs through extensive
cool temperate rainforest. Here, it is relatively wide and its bed consists of exposed shelves of
bedrock. Other lichens present include characteristic saxicolous taxa such as Paraporpidia
leptocarpa (C.Bab. & Mitt.) Rambold & Hertel, species typical of habitats subject to periodic
disturbance, for example Baeomyces heteromorphus Nyl. ex C.Bab. & Mitt., Trapelia coarc-
tata (Sm.) M.Choisy and Stereocaulon ramulosum (Sw.) Räusch., and a small suite of aquatic
species, including Hymenelia lacustris (With.) M.Choisy and an undescribed but well-known
species of Trapelia. This site is the type and only known locality of Porina australis
P.M.McCarthy & Kantvilas, which also inhabits seasonally inundated, siliceous rock in the
river bed (McCarthy & Kantvilas 2017).
New records
1. Rhizocarpon bicolor Elix & P.M.McCarthy, Australas. Lichenol. 85, 51 (2019)
R. badioatrum (Flörke) Th.Fr.: Australian collections (see McCarthy & Elix 2014)
R. eupetraeoides (Nyl.) Blomb. & Forsell: Australian collections (see McCarthy & Elix 2014)
This species was described recently from siliceous rocks in eastern New South Wales, the
Australian Capital Territory and Victoria (Elix & McCarthy 2019).
SPECIMENS EXAMINED
Tasmania: ● summit, Mt Murchison, 41°49’S, 145°37’E, 1275 m alt., on quartzite, F.N. Lakin
[G.C. Bratt76/1141], xi.1976 (HO) [psoromic acid (major), rhizocarpic acid (minor) by TLC];
● Gingerbread Track, Mt Rufus, Cradle Mountain Lake St Clair Natl Park, 42°08’S, 146°06’E,
1140 m alt., on coarse sandstone outcrops in alpine heathland, G. Kantvilas 253/12, 18.iii.2012
(HO) [bourgeanic acid (major) by TLC].
2. Rhizocarpon geminatum Körb., Syst. Lich. German. 259 (1855)
Reported from alpine, siliceous rocks in the Australian Capital Territory, the south and central-
west of New South Wales and Victoria by McCarthy & Elix (2014), it is also known from
Europe, Arctic Eurasia, Greenland, Turkey, Central Asia, North America, Bolivia, Argentina,
islands in the South Atlantic Ocean, Antarctica and New Zealand.
SPECIMEN EXAMINED
Tasmania: ● Lake Kaye, 41°54’S, 146°31’E, 1140 m alt., on large basalt boulder in alpine
meadow subject to seasonal inundation, G. Kantvilas 80/00, 8.iii.2000 (HO) [bourgeanic acid
(major), or bourgeanic acid (major) and gyrophoric acid (major) by TLC].
3. Rhizocarpon aff. lusitanicum (Nyl.) Arnold, Flora 53, 478 (1870) Fig. 10
Lecidea lusitanica Nyl., Flora 48, 605 (1865)
Thallus nondescript, indistinguishable from the host. Prothallus not apparent. Apothecia
moderately numerous, dull black, lecideine, round or broadly ellipsoid in outline, (0.27–)
0.43(–0.62) mm diam. [n = 37], solitary, innate between the host areoles to adnate; margin
entire, usually becoming excluded, concolorous with the disc; disc moderately to strongly
convex or almost subglobose, epruinose. Proper excipulum annular, uniformly to dark brown,
60–85 µm thick. Epihymenium blackish, c. 20 µm thick, K+ purple, N+ deep purple-brown.
Hypothecium brownish black, 150–200 µm thick. Hymenium 100–160 µm thick, hyaline,
amyloid. Paraphysoids tightly conglutinate, anastomosing, 1–2(–3) µm thick; apical cells
2–4(–4.5) µm wide, medium to dark brown. Asci narrowly to broadly clavate, (4–)8-spored,
75–100 × 22–35 µm. Ascospores dark greenish brown to brown-black, mostly narrowly to
broadly ellipsoid, submuriform at maturity and with 5–8 cells in optical section, 18–27(–30) ×
9–14 µm [n = 27]; perispore 2–4 µm thick. Pycnidia not seen.
Chemistry: no substances detected by TLC.
Apothecial morphology and anatomy in the Tasmanian specimen are a very close match for
R. lusitanicum as documented by Poelt & Hafellner (1982). That species, initially a parasite of
Pertusaria sens. lat., is known from southern and south-eastern Europe and Macaronesia. It
can become a partly yellowish (with rhizocarpic acid) and independent lichen, or it can remain
a greyish and nondescript parasymbiont (without rhizocarpic acid; Poelt & Hafellner 1982;
Breuss 1988). Given the sparse Tasmanian material and its novel host, additional collections
are required to conrm the status of this species.
SPECIMEN EXAMINED
Tasmania: ● c. 1 km W of Circular Marsh, on E side of Pine River, 41°59’S, 146°28’E, 860 m
alt., lichenicolous on Lepra sp., in turn growing on dolerite boulders, G. Kantvilas 74/14,
20.ii.2014 (HO).
4. Rhizocarpon polycarpum (Hepp) Th.Fr., Lichenogr. Scand. 2, 617 (1874)
Previously recorded from Western Australia, New South Wales, the Australian Capital Terri-
tory and Victoria (McCarthy & Elix 2014); also in Europe, Arctic Eurasia, North Africa,
Turkey, China, the Bering Strait, North America, southern South America, islands in the South
Atlantic Ocean, Antarctica and New Zealand.
SPECIMENS EXAMINED
Tasmania: ● Lake Kaye, 41°54’S, 146°31’E, 1140 m alt., on basalt boulders in alpine
heathland, G. Kantvilas 95/00, 8.iii.2000 (HO) [norstictic acid (major), connorstictic acid
(trace)]; ● Bisdee Tier [near Spring Hill], 42°26’S, 147°17’E, 640 m alt., on plates of dolerite
bedrock in rocky grassland, G. Kantvilas 134/09, 11.iii.2009 (HO) [stictic acid (major), bourg-
eanic acid (major) and satellite compounds by TLC].
AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
48 49
Key to the species of Rhizocarpon in Australia
1 Thallus yellow-green; cortex containing rhizocarpic acid...................................................2
1: Thallus whitish, brown, green or grey; cortex lacking rhizocarpic acid..............................8
2 Thallus with punctiform to capitate soralia; soredia yellow-green, granular.....R. ridescens
2: Thallus lacking soralia..........................................................................................................3
3 Ascospores 1-septate............................................................................................................4
3: Ascospores submuriform to muriform ................................................................................6
4 Ascospores 20–35 × 11–18 µm..............................................................................R. bicolor
4: Ascospores 12–23 × 6–10 µm..............................................................................................5
5 Medulla yellow; containing only rhizocarpic acid..............................................R. adarense
5: Medulla white; containing rhizocarpic and stictic or perlatolic acids............R. superciale
6 Thallus forming a pseudolecanorine margin around apothecia....................R. lecanorinum
6: Thallus not forming a pseudolecanorine margin around apothecia..........…………….……7
7 Thallus initially parasitic on the lichen Aspicilia sens. lat.; upper surface usually pale
green; containing rhizocarpic and ± norstictic acids ........................................R. viridiatrum
7: Thallus not parasitic on other lichens; upper surface predominantly yellow; containing
rhizocarpic and psoromic, barbatic or 2’-O-methylperlatolic acids ..........R. geographicum
8 Initially lichenicolous on Lepra sp. .......................................................R. aff. lusitanicum
8: Never lichenicolous ............................................................................................................ 9
9 Ascospores 1-septate .........................................................................................................10
9: Ascospores 3-septate to submuriform or muriform ..........................................................13
10 Mature ascospores hyaline, 17–22 × 8–11 µm; medulla I+ blue ...............R. polycarpum
10: Mature ascospores dark grey-green to dark brown; medulla I+ blue or I– .................... 11
11 Medulla white, I+ blue ...................................................................................... R. vigilans
11: Medulla yellow or white, I– ............................................................................................ 12
12 Medulla yellow above; ascospores 12–22 × 6–10 µm ...................... R. avomedullosum
12: Medulla uniformly white; ascospores 20–35 × 11–18 µm ................................ R. bicolor
13 Mature ascospores predominantly 3-septate, rarely 1-septate, occasionally with 1 or 2
longitudinal or diagonal septa, colourless (collapsed post-mature ascospores can be dark
brown); medulla I+ blue ....................................................................................R. distinctum
13: Mature ascospores submuriform to muriform, with 8–50 cells in optical section, colour-
less to dark brown; medulla I– .............................................................................................. 14
14 Mature ascospores colourless ......................................................................................... 15
14: Mature ascospores dark grey-green to dark brown ........................................................ 19
15 Ascospores mostly submuriform, 16–37 µm long .......................................................... 16
15: Ascospores eumuriform, 30–50 µm long ....................................................................... 18
16 Apothecia (0.19–)0.45(–0.77) mm diam. .......................................................R. reductum
16: Apothecia (0.43–)0.86(–1.38) mm diam. .......................................................................17
17 Thallus without a prothallus, lacking lichen substances; apothecial margin black; proper
excipulum and hypothecium producing a deep red leachate in K ..............R. austroalpinum
17: Thallus with a distinct marginal prothallus, containing hypostictic acid (major); apothec-
ial margin concolorous with the black disc or somewhat to considerably paler, often retaining
a whitish inner collar; proper excipulum and hypothecium not producing a deep red leachate
in K.....................................................................................................................R. torquatum
18 Upper surface pale brown; proper margin thick, swollen; thallus lacking lichen substances;
on siliceous rocks [Macquarie Island] ................................................................... R. lavatum
18: Upper surface white to grey; proper margin not swollen; thallus with stictic acid; usually
on calcareous rocks ..............................................................................................R. petraeum
19 Asci 1-spored; ascospores 50–75 × 20–30 µm .............................................. R. disporum
19: Asci (1–)2–8-spored; ascospores smaller ...................................................................... 20
20 Ascospores 17–38 × 9–19 µm, (4–)8 per ascus .............................................................. 21
20: Ascospores 30–55 × 17–25 µm, (1–)2–6 per ascus ........................................................ 22
21 Apothecia 0.19–0.44 mm diam.; proper exciple 35–45(–50) µm thick; ascospores 17–24
× 9–14 µm, with (3–)4–7(–8) cells in optical section ............................................R. exiguum
21: Apothecia 0.27–1.08 mm diam.; proper exciple 60–110(–140) µm thick; ascospores 22–
38 × 10–19 µm, with (7–)9–15(–17) cells in optical section ............................. R. intersitum
22 Paraphyses anastomosing; ascospores (1–)2(–4) per ascus; apothecia ± elevated, uniform-
ly black; on comparatively dry montane rocks, not associated with water bodies ...................
...........................................................................................................................R. geminatum
22: Paraphyses ± simple; ascospores 2–4(–6) per ascus; apothecia immersed, with a white
rim; on rocks in and around Tasmanian alpine lakes .............................R. austroamphibium
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GK 202/16 • - - - - - - - -
GK 234/16 • - - - - - - - -
GK 376/16 • - - - - - - - -
GK 313/00 • - - - - - - - -
MLW 1971 • - - - - - - - -
GK 416/04
-
•
- - - - - - -
AM 5123
-
•
- - - - - - -
GK 570/02 -
-
• - - - - - -
GK 16/00 - - - - - - -
• -
GK 790/01 - - - - - - -
• -
GK 150/15 - - - - - - -
• -
GK 147/16 - - - - - - -
• -
GK 251/16 - - - - - - -
• -
GK 605/02 - - - - - - -
• -
GCB 75/490 - - - - - - -
• -
GK 170/02 - - - - - -
• -
GK 8/06 - - - - - -
• -
GK 16/13 - - - - - -
• -
GK 93/16 - - - - - -
• -
GK 318/12 - - - - - -
• -
GK 593/81 - - - - - -
• -
GK 325/12 - - - - - -
• -
GK 944/81A - - - - - -
• -
GK 363/12 - - - - - -
• -
GK 669/12 - - - - - -
• -
GK 406/16 - - - -
-
• -
GK 30/17 - - - - -
• -
GK 1/00 - - - - -
• -
GCB 75/387 - - - - -
• -
GK 87/13 - - - - - -
• -
GK 726/12 - - - - - -
• -
GK 173/17 - - - - -
• -
GK 610/03 - - -
• - - -
• -
GK 519/03 - - - - - - - -
•
GK 92/18 - - - - - - - -
•
GK 1358/01 - - - - - - - -
•
GK 117/17 - - - - - - - -
•
bourgeanic acid
gyrophoric acid
psoromic acid
barbatic acid
cryptostictic acid
hypostictic acid
constictic acid
stictic acid
nil
Table 1. Secondary metabolites of Rhizocarpon reductum in Tasmania. The satellite substances
constictic, cryptostictic, menegazziaic and peristictic acids, as well as hypostictic acid, are not
included when present in only trace quantities with stictic acid.
• = major quantity,
= minor quantity.
AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
52 53
Figure 1. Rhizocarpon austroalpinum. A, B, holotype; C, G. Kantvilas 136/12. Scales: 2 mm.
Figure 2. Rhizocarpon austroalpinum (G. Kantvilas 136/12). Habit of thallus and apothecia.
Scale: 0.5 mm.
AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
54 55
Figure 3. Apothecial sections (semi-schematic). A, Rhizocarpon austroalpinum (holotype). B,
R. torquatum (holotype). C, R. reductum (G. Kantvilas 363/12). Scale: 0.2 mm.
Figure 4. Ascospores. A, Rhizocarpon austroalpinum (holotype). B, R. torquatum (holotype).
Scale: 20 µm.
AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
56 57
Figure 5. Rhizocarpon exiguum (holotype). Scales: 1 mm.
Figure 6. Rhizocarpon exiguum (holotype). A, Vertical section of an apothecium (semi-
schematic); B, Ascospores; C, Ascospores of Rhizocarpon intersitum (G. Kantvilas 99/94).
Scales: A = 0.2 mm; B, C = 20 µm.
AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
58 59
Figure 7. Rhizocarpon intersitum: morphological variation in Tasmania. A, G. Kantvilas
206/05; B, G. Kantvilas 1135/01; C, G. Kantvilas 99/94; D, G. Kantvilas 128/14. Scales: 2 mm.
Figure 8. Rhizocarpon reductum, morphological variation in Australia. A, G. Kantvilas 202/16;
B, G. Kantvilas 16/00; C, G. Kantvilas 363/12 (A–C, Tasmania); D, P.M. McCarthy 4666
(Southern Tablelands, New South Wales). Scales: 2 mm.
AUSTRALASIAN LICHENOLOGY 86, January 2020 AUSTRALASIAN LICHENOLOGY 86, January 2020
60 61
Figure 9. Rhizocarpon torquatum (holotype). Scales: 2 mm.
Figure 10. Rhizocarpon aff. lusitanicum (G. Kantvilas 75/14). Scale: 2 mm.
