Newly recorded corticolous lichens for Vietnam

Abstract

This study contributes to the diversity of Vietnamese lichens with four new records for the country, including Nigrovothelium bullatum and Pyrenula confinis in urban areas and Leptogium phyllocarpum and Gabura fascicularis in central highlands. Amongst these, G. fascicularis is the first record of Arctomiaceae in Vietnam. The morphology, distribution, ecology and illustrations of all four species are provided.

Full text

Taiwania 69(1): 104‒108, 2024
DOI: 10.6165/tai.2024.69.104
104
NOTE
Newly recorded corticolous lichens for Vietnam
Thi Thanh Van LE1,*, Thanh Luc NGUYEN2, Nguyen Khanh Trinh TRAM1, Thien Tam LUONG1,3,
Thi Phi Giao VO1
1. Department of Ecology-Evolutionary Biology, University of Science, Vietnam National University Ho Chi Minh City, 227 Nguyen
Van Cu, District 5, Ho Chi Minh City, Vietnam. 2. Southern Institute of Ecology, Institute of Applied Materials Science, Vietnam
Academy of Science and Technology, 1D, TL29 Street, Thanh Loc Ward, District 12, Ho Chi Minh City, Vietnam. 3. Biodiversity Unit,
FI-20014 University of Turku, Finland. *Corresponding author’s email: thanhvanle0812@gmail.com; Phone no.: +84 352250901
(Manuscript received 1 September 2023; Accepted 22 December 2023; Online published 8 March 2024)
ABSTRACT: This study contributes to the diversity of Vietnamese lichens with four new records for the country, including
Nigrovothelium bullatum and Pyrenula confinis in urban areas and Leptogium phyllocarpum and Gabura fascicularis in central
highlands. Amongst these, G. fascicularis is the first record of Arctomiaceae in Vietnam. The morphology, distribution, ecology
and illustrations of all four species are provided.
KEY WORDS: Arctomiaceae, Collemataceae, Gabura, Ho Chi Minh City, new records, Pyrenulaceae, Trypetheliaceae, urban lichen.
INTRODUCTION
The first paper on the lichenized fungi (commonly
known as lichen) of Vietnam dates back to 150 years ago,
of Krempelhuber (1873). Thereafter, the number of
recorded species had slowly arisen by sporadic reports
mainly by foreign lichenologists (Müller, 1889, 1891; de
Lesdain, 1908; Ahti, 1961; Culberson and Culberson,
1968; Culberson and Hale, 1973). The voucher specimens
were collected by French and scattered in herbaria all
over the world, such as BM, EGR, G, H, PC, TUR. After
the interruption during the French colonial time and the
Vietnam war, Vězda (1977) added 41 species to the
epiphyllous lichens to Vietnam, including three new
species, based on the collection of T. Pócs, Gy. Topál, and
J. Zsolt; Ahti (1986, 1991) also examined Vietnamese
specimens of Cladonia which included two new species.
Studies on Vietnamese lichen started to bloom after the
publication of the first checklist for the country by
Aptroot and Sparrius (2006). They recognized 275
species and estimated 1.000 species in total to occur.
Since then, several studies on various groups of
Vietnamese lichens have been published not only by
foreign lichenologists but also by Vietnamese ones,
which resulted in 189 new records for the country and 11
new species for science (Vo, 2009; Nguyen et al., 2010,
2011a,b; Jayalal et al., 2013; Joshi et al., 2013a,b,c,d,
2014, 2015a,b,c, 2017, 2018, 2019; Gueidan et al., 2014).
Most of the surveys of Vietnamese lichens were based
on specimens collected in rural or low-human-impacted
areas like forests and mountains. As a result, the urban
lichens have been overlooked but new things are waiting
to be discovered. In 2020, we collected more than 60
species of lichens and bryophytes in Ho Chi Minh City
(one of the biggest urban cities in Vietnam known as
Saigon) in the project aimed to study the relationship
between lichens-bryophytes and air quality. Soon after
then, records of bryophytes for Vietnam from this project
were published (Nguyen et al., 2021) while all lichen
specimens need treating more. This paper discusses four
new records for corticolous lichen in Vietnam, including
two species recorded in that project together with two
species from the Central Highlands.
MATERIALS AND METHODS
Materials in the study were collected in Ho Chi Minh
City from 2019 to 2020, which have been preserved in the
herbarium of University of Science–Vietnam National
University Ho Chi Minh City (PHH), except Leptogium
phyllocarpum (Pers.) Mont. and Gabura fascicularis (L.)
P.M. Jørg, collected in Lam Dong Province in 2020 and
2022, respectively and deposited in the herbarium of
Southern Institute of Ecology (SGN).
The identification was done with morphological and
anatomical characters. Spot-test reactions on the surface
of thallus were observed based on methods using
potassium hydroxide solution (K) and sodium
hypochlorite solution (C) (Orange et al., 2001). Free-
hand sections of apothecia and thallus were examined
with Lactophenol cotton blue (LCB) and Lugol’s Iodine
(0.3% IKI) regarded as staining solutions for hyphae and
ascospores in order. These processes are done with a
Kruss MSZ5000-IL stereo microscope and a Nikon
model eclipse E400 optical microscope. Simultaneously,
microscopic details were captured by using a Leica
DM750 compound microscope with an attached digital
camera Leica DFC290HD. The key to genera of Bogor,
Cibodas and Singapore (2003), accessed at
https://archive.bgbm.org/Sipman/keys/Javagenera.htm
and the world keys for each genus were mainly utilized if
applicable. The results would be compared with original
descriptions and confirmed by consultation with experts
afterward.

2024 Le et al.: corticolous lichens for Vietnam
105
Fig. 1. Gabura fascicularis A. fresh thallus in the natural habitat; B. dry thallus; C. an acicular ascospore. Scale: A, B = 1 mm; C = 10 μm.
TAXONOMIC TREATMENT
Gabura fascicularis (L.) P.M. Jørg. [as 'fasciculare'],
Lichenologist 46(4): 594 (2014) Fig. 1A–C
≡ Arctomia fascicularis (L.) Otálora & Wedin, Lichenologist 45(3):
302 (2013)
Thallus crustose to subfoliose, approximately 1 cm in
diameter, cushion-shaped, closely attached, gelatinous,
olive-green when wet, black when dry, ecorticate. Lobes
undeveloped; margin indistinct. Photobiont Nostoc.
Apothecia several, sessile, lecanorine, 0.3–0.8 mm in
diam.; margin smooth. Discs concave to flat, red-brown
to dark-brown when dry. Hymenium hyaline, I+ blue;
epihymenium brown pigmented, I-. Asci cylindrical, 8-
spored. Ascospores persistently hyaline, acicular, 90–96
× 3–6 μm, transversely 8–15 septate, with thin wall and
septa.
Chemistry: Thallus K-, C-, KC-, UV-
Distribution and ecology: Its occurrence has been
reported widely in mild-temperate regions and also found
in Thailand’s tropical forests (Aptroot et al., 2007). We
found this species growing on an exposed branch in the
secondary forest with sunny, semi-dry, and humid
circumstances, in the central highlands of Vietnam.
Specimen examined: VIETNAM: LAM DONG. Bidoup-
Nui Ba National Park, Krong No Ranger Forest Station (N12°15'43",
E108°26'35"), on bark, 687 m elev., 3 May 2022, T.L. Nguyen B-
2022467 (SGN).
Remarks: This is the first report of the Arctomiaceae
for the country. Our material has poorly developed thallus
and indistinct lobes, compared to specimens recorded in
some regions. This species is separated from the Collema
by its small size, cushion-shaped thallus and extremely
narrow ascospores.
Leptogium phyllocarpum (Pers.) Mont., Annls Sci. Nat.,
Bot., sér. 3 10: 134 (1848)
Fig. 2A–C
Thallus foliose, corticate, wrinkled on both surfaces,
gelatinous and swelling when wet, grey, sometimes pale
yellow near the margin. Lobes developed, ascending.
Soredia, isidia absent. Photobionts in chains of Nostoc.
Apothecia usually near the lobe margin, sessile, 1.5–2
mm wide; disc red-brown to dark-brown, slightly
concave to flat; margin thalline, with swelling, wrinkled

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106
Fig. 2. A–C. Leptogium phyllocarpum (A, B. thallus with marginal apothecia; C. eight muriform ascospores within ascus; D–G.
Nigrovothelium bullatum (D. habitus; E. vertical section of perithecium; F. ascus with 8 spores; G. transversely septate spores); H–
J, Pyrenula confinis (H. habitus; I. vertical section of perithecium; J. muriform spores). Scale: A, B, D, H = 1 mm; C, F, G, J = 10 μm;
E, I = 100 μm. (C, F, G, LPCB preparation; E, I, J, water preparation)

2024 Le et al.: corticolous lichens for Vietnam
107
and persistent lobules. Hymenium hyaline; epihymenium
slightly brown; hamathecium not anastomosing. Asci
cylindrical-clavate, 120–140 × 15–25 μm, I+ blue in outer
layer and apical structure after treating with KOH, 8-
spored. Ascospores uniseriate, hyaline, 15–25 x 10–12
μm, muriform with 4–5 transverse septa, 1–2 longitudinal
ones, I-.
Chemistry: Thallus K-, C-, KC-, UV-
Distribution and ecology: Its occurrence has been
reported in the pantropical and subtropical areas (Nash,
2004). The Vietnamese material was found on a twig in
the evergreen broad-leaved forest mixed with conifers,
with the monthly average humidity around 83.9–97.1%.
Specimen examined: VIETNAM: LAM DONG. Bidoup-
Nui Ba National Park, The Bidoup Forest Dynamics Plot (N 12°10'28",
E108°41'12”), on twig, 1553 m elev., 10 July 2020, T.L. Nguyen F-
2020136 (SGN).
Remarks: Leptogium phyllocarpum can be easily
distinguished by anastomosing lobes and the apothecia
forming lobate thalline margin among the species of this
genus in Vietnam.
Nigrovothelium bullatum Lücking, Upreti & Lumbsch,
in Lücking, Nelsen, Aptroot, Benatti, Binh, Gueidan,
Gutiérrez, Jungbluth, Lumbsch, Marcelli, Moncada,
Naksuwankul, Orozco, Salazar-Allen & Upreti,
Lichenologist 48(6): 655 (2016) Fig. 2D–G
Thallus shiny, olive-green or yellow, verrucose-
bullate, corticate, thick. Medulla white. Ascomata
perithecial, free to fused, sessile, carbonized, exposed by
a small dot; ostioles apical, separate. Hymenium not
inspersed; hamathecium branched, anastomosing. Asci
clavate. Ascospores hyaline, fusiform, 20–22.5 × 5–7.5
μm, 3-septate with diamond-shaped locules.
Chemistry: Thallus K-, C-, KC-, UV-
Distribution and ecology: Nigrovothelium bullatum
was described based on specimens collected from India
and Thailand (Lücking et al., 2016). The specimens from
Vietnam were collected on exposed bark in semi-dry to
dry habitats.
Specimens examined: VIETNAM: Ho Chi Minh CITY. Thu
Duc City: University of Science (N10°52'30", E106°47'49"), on the bark
of Hopea odorata Roxb., 33 m elev., 17 February 2020, Nguyen, Tram,
Le & Vo VU20061 (PHH). District 7: Tan Thuan Export Processing
Zone (N10°45'56", E106°44'58"), on the bark of Enterolobium
cyclocarpum (Jacq.) Griseb., 3 m elev., 24 March 2020, Nguyen, Tram,
Le & Vo VU20180a (PHH). Go Vap District: Gia Dinh park
(N10°48'44", E106°40'31"), on the bark of Hopea odorata Roxb., 12 m
elev., 18 March 2020, Nguyen, Tram, Le & Vo VU20155 (PHH).
Remarks: All of the three Nigrovothelium species are
present in Vietnam, including N. tropicum (Ach.)
Lücking, M.P. Nelsen & Aptroot (Aptroot and Sparrius,
2006), N. inspersotropicum Aptroot & Diederich
(Gothamine et al., in prep.), and N. bullatum that is newly
reported here.
Nigrovothelium bullatum resembles N. tropicum but
the latter differs in smooth thallus instead of strongly
verrucose-bullate one (Aptroot and Lücking, 2016).
Pyrenula confinis (Nyl.) R.C. Harris, More Florida
Lichens, Incl. 10 Cent Tour Pyrenol. (New York): 109
(1995) Fig. 2H–J
Thallus immersed to the substrate, greyish to
yellowish or pale green, smooth, ecorticate, thin.
Ascomata perithecial, black, solitary, open with black,
apical ostioles, prominent on the thallus, emergent,
carbonized. Hymenium clear; hamathecium unbranched,
I-. Asci 8-spored. Ascospores brown, oval to ellipsoid
with rounded ends, 15–21 × 10–13 μm, muriform, 3
transverse and frequently 2 longitudinal septa; locules
rounded, lenticular.
Chemistry: Thallus K-, C-, KC+ slightly red, UV+
yellow.
Distribution and ecology: This is a pantropical
species (Aptroot et al., 2008). The Vietnamese specimens
are observed on tree trunks in a couple of plantations at
an altitude of 03–33 m.
Specimen examined: VIETNAM: Ho Chi Minh CITY. Thu
Duc City: University of Science (N10°52'30", E106°47'49"), on the bark
of Mimusops elengi, 33 m elev., 16 February 2020, Nguyen, Tram, Le
& Vo VU20034, VU20037, VU20040 (PHH). District 6: Phu Lam Park
(N10°44'50", E106°37'28"), on the bark of Peltophorum pterocarpum
(DC.) Backer ex K.Heyne, 3 m elev., 21 February 2020, Nguyen, Tram,
Le & Vo VU20102, VU20104 (PHH).
Remarks: Pyrenula confinis is distinguished from
most Pyrenula species recorded in Vietnam by its brown,
muriform ascospores. Pyrenula macularis (Zahlbr.) R. C.
Harris also shares these characteristics, yet it can be
distinguished from the present species by larger
ascospores (longer than 30 μm) with more transverse
septa (8 septa) (Aptroot et al., 2008).
ACKNOWLEDGMENTS
We are deeply grateful to Robert Lücking, André Aptroot,
Mónica A. G. Otálora for their support for identification, and
helpful comments from Hiroshi Hadara on the manuscript. The
authors thank the managers and staff of Bidoup – Nui Ba National
Park for their collecting permits. This study was supported by
Youth Science and Technology Development Center (project no.
25/2019/HĐ-KHCN VƯ), and partly by the project “Innovative
Approaches to Biodiversity Discovery and Characterisation in
Vietnam” (VIETBIO) under grant number 01DP17052.
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