Introduction
The lichen genus Carbacanthographis Staiger & Kalb was established by Staiger & Kalb (2002). It comprises species in the family Graphidaceae characterized by a convergent, carbonized exciple, labia covered with a distinct white pruinose layer in the upper part, warty periphysoids, and I− or weakly I+, muriform or trans-septate ascospores. So far the genus is known to include 17 species world-wide (Staiger Reference Staiger2002; Kalb Reference Kalb2004; Archer Reference Archer2006, Reference Archer2007; Lücking et al. Reference Lücking, Archer and Aptroot2009) and has been reported from the Neotropics, Africa, Australia, Singapore, Japan and the Solomon Islands. Vegetative propagules are generally rare in Graphidaceae, but in our recent studies in the family, we have discovered one sorediate species which belongs to the genus Carbacanthographis. This species is formally described in the present paper. A key to the species of Carbacanthographis so far known is also provided.
Materials and Methods
The study is based on herbarium specimens housed at the Ajrekar Mycological Herbarium (AMH). Sections of thalli and ascomata were mounted in water, 10% KOH (K), Lugol's solution (I), and lactophenol cotton-blue (LPCB). All measurements were made on material mounted in water. Secondary products were identified by thin-layer chromatography using standard methods (Culberson & Kristinsson Reference Culberson and Kristinsson1970; Culberson Reference Culberson1972; White & James Reference White and James1985) with the solvent systems toluene-dioxane-acetic acid (180:45:5) and toluene-ethyl acetate-formic acid (139:83:8). The plates were examined under UV light (365 nm).
The Species
Carbacanthographis marcescens (Fée) Staiger & Kalb
Biblioth. Lichenol. 85: 109 (2002).—Graphis marcescens Fée, Essai Crypt. Exot. (Paris) 1: 38 (1825).
(Fig. 1)
Fig. 1. Carbacanthographis marcescens, habitus (76.584—AMH). Scale = 1mm
Fig. 2. Carbacanthographis sorediata (holotype, AMH). A–C, habitus; D, vertical section of ascocarp and soralium; E, warty periphysoids; F, ascospores. Scales: A–C = 1mm; D = 50μm, E–F = 10 μm.
Remarks. Carbacanthographis marcescens has earlier been recorded from India as Graphina marcescens Fée (Patwardhan & Kulkarni Reference Patwardhan and Kulkarni1976; Makhija et al. Reference Makhija, Adawadkar and Patwardhan1992) and can easily be identified by its laterally carbonized exciple, warty periphysoids, powdery, white thalline cover, small muriform ascospores, and by the presence of salazinic, protocetraric and norstictic acids in the thallus. The species is widely distributed and occurs in Australia, Brazil, Cameroon, Cuba, Guyana, India, Solomon Islands, Thailand, and the USA. In India it has been collected in the evergreen forests of Kerala and Tamil Nadu situated in the Western Ghats and in the tropical evergreen rain forest of Andaman Islands. Corticolous pyrenocarpous and graphidaceous lichens and the thelotremes predominate in the lichen biota of the Andaman Islands.
Specimens examined (all AMH). India: Andaman Islands: South Andaman, Tarmugli Island, near Wandoor, 1985, P. K. Sethy & P. G. Patwardhan 85.1945, 85.1946; Redskin Islands, Wandoor, 1985, P. K. Sethy & M. B. Nagarkar 85.1991, 85.1992; ibid., P. G. Patwardhan & M. B. Nagarkar 85.1999, 85.2000, 85.2002, 85.2006, 85.2007. Kerala: Munnar-Kodai Road, below Yellapattii, 1976, P. G. Patwardhan & M. B. Nagarkar 76.584; Cardamom hills, Devicolam-Kumily Road, 17 km from Devicolam, 1976, P. G. Patwardhan & A. V. Prabhu 76.695; Thekadi, near Periyar house, 1976, P. G. Patwardhan & M. B. Nagarkar, 76.949. Tamil Nadu: Kodaikanal, Silver Caskade, 1975, P. G. Patwardhan & A. V. Prabhu 75.60, 75.406, 75.420, 75.421; Kodailkanal, Kodai-Munnar Road, 10 km to Berijam lake, 1975, P. G. Patwardhan & A. V. Prabhu 75.128, 75.160; Kodaikanal, near Golf Club, 1975, P. G. Patwardhan & A. V. Prabhu 75. 189; Dastoor Villa, Kodai lake, 1975, P. G. Patwardhan & A. V. Prabhu 75.330, near Daisy Bank, 1975, P. G. Patwardhan & A. V. Prabhu 75.356.
Carbacanthographis sorediata B. O. Sharma, Makhija & Khadilkar sp. nov
Similis Carbacanthographide marcescente sed thallo sorediato, ascosporis majoribus et acido consalazinico differt.
Typus: India, Tamil Nadu, Agasthyamalai (Agasthi hills), Upper Kodayar, 24 January 1983, P. G. Patwardhan & P. K. Sethy 83.250 (AMH—holotypus)
(Fig. 2A– F)
Thallus crustose, corticolous, epiphloeodal, greenish grey, finely cracked, with a thin pseudocortex, sorediate; soralia whitish, granular, with the photobiont layer being pushed upwards by vertical hyphae in the thallus (Fig. 2D).
Ascocarps lirellate, conspicuous, light pinkish to creamy, emergent, undulate, with conspicuous powdery pruinose cover, simple to branched, curved, up to 4 mm long, ends acute or round. Disc slit-like, covered laterally with light pinkish pruina and coated with warty periphysoids. Proper exciple convergent, laterally carbonized, base brown. Epithecium absent. Hymenium hyaline, not inspersed, I−, 60–100 μm high. Paraphyses simple. Periphysoids short, distinctly warty. Asci 8-spored. Ascospores hyaline, fusiform, submuriform, with 7–8 transverse and 1–2 longitudinal septa per segment, 17·5–27·5 × 7·5–10 μm, I+ colour reaction weak.
Fig. 3. Distribution of Carbacanthographis species in India; ● C. marcescens, ■ C. sorediata.
Chemistry. Salazinic and consalazinic acids present.
Remarks. Carbacanthographis sorediata stands distinct amongst all the known species of Carbacanthographis in having a sorediate thallus with a unique type of soralia: in sections it appears as if the photobiont layer is pushed upwards by vertical hyphae in the thallus, to eventually form the soralia. Carbacanthographis marcescens can be differentiated in lacking soralia and having smaller ascospores of 12–17 × 5–7 μm, and a slightly different chemistry. Carbacanthographis amicta (Nyl.) Staiger & Kalb and C. salazinica also contain salazinic acid, but differ from the new species in having a thallus without soredia and a completely carbonized exciple.
The new species Carbacanthographis sorediata is confined to the Western Ghats (Fig. 3), which form a practically unbroken relief dominating the western coast of the Indian peninsula for almost 1600 km. From a botanical point of view, the Western Ghats occupy a special position on the Indian subcontinent for their interesting flora and are one of the richest lichen sites in India. The species was collected in the Agasthyamalai (Agasthi hills) in tropical moist evergreen montane forests at an elevation of c. 1800 m.
Additional specimens examined. India: Tamil Nadu: Agasthyamalai (Agasthi hills), Upper Kodayar, 1983, P. G. Patwardhan & P. K. Sethy 83.249, 83.356, 83.357 (AMH).
World-wide key to the species of Carbacanthographis
1 Thallus isidiate or sorediate ... 2
Thallus neither isidiate nor sorediate ... 3
2(1) Thallus isidiate; asci (4–) 6–8-spored; protocetraric acid present; Australia ... ... C. hertelii Kalb & Staiger
Thallus sorediate; asci 8–spored; salazinic and consalazinic acid present; India ... ... C. sorediata B. O. Sharma et al.
3(1) Excipular base not carbonized ... 4
Excipular base carbonized ... 8
4(3) Ascospores trans-septate ... 5
Ascospores muriform ... 6
5(4) Norstictic acid present; Vietnam ... C. induta (Müll. Arg) Lücking
Stictic acid present; Japan ... ... C. iriomotensis (M. Nakan.) M. Nakan. & Kashiw.
6(4) Salazinic acid (major), protocetraric and norstictic acid (trace) present; ascospores 12–17 × 5–7 μm; Australia, Brazil, Cuba, Dominica and India ... ... C. marcescens (Fée) Staiger & Kalb
Stictic acid present ... 7
7(6) Asci 1-spored; ascospores c. 100 μm long ... C. cleitops (Fée) Lücking
Asci 6–8-spored; ascospores 47–75 × 18–30 μm; Cuba, Dominica ... ... C. triphoroides (M. Wirth & Hale) Lücking
8(3) Ascospores trans-septate ... 9
Ascospores muriform ... 12
9(8) Ascospores 4 locular; asci 8-spored; ascospores 18–20 × 8–10 μm; psoromic acid present; Solomon Islands ... C. alloafzelii (A.W. Archer) A.W. Archer
Ascospores more than 4 locular ... 10
10(9) Ascospores large, more than 50 μm long; asci 4–8–spored; ascospores 55–100 × 7–9 μm; protocetraric and lichexanthone present; Brazil, Paraguay ... ... C. candidata (Nyl.) Staiger & Kalb
Ascospores small, less than 50 μm long ... 11
11(10) Ascospores 23–35 × 6–7 μm in size; stictic, constictic, menegazzic and hypostictic acids present; Brazil ... C. stictica Staiger & Kalb
Ascospores 20–25 × 6–8 μm; protocetraric and lichexanthone acids present; Brazil ... C. chionophora (Redinger) Staiger & Kalb
12(8) Lichen substances absent; asci 8–spored; ascospores 20–40 μm long; Brazil ... ... C. coccospora (Aptroot) Aptroot & Lücking
Lichen substances present ... 13
13(12) Ascospores more than 50 μm long ... 14
Ascospores less than 50 μm long ... 15
14(13) Asci 8–spored; ascospores 55–90 × 11–18 μm; protocetraric acid and lichexanthone present; Brazil ... C. subalbotecta Staiger & Kalb
Asci 1–spored; ascospores 120–180 × 25–30 μm; stictic, constictic and cryptostictic acids present; Brazil ... C. crassa (Müll. Arg.) Staiger & Kalb
15(13) Salazinic acid present ... 16
Salazinic acid absent ... 17
16(15) Ascospores 14–18 × 6–7 μm; only salazinic acid present; New Pacific and Japan ... C. amicta (Nyl.) Staiger & Kalb
Ascospores 19–23 × 7–8 μm; salazinic (major), consalazinic, norstictic and protocetraric (trace) acids present; Australia, Indonesia ... ... C. salazinica (A.W. Archer) A.W. Archer
17(15) Ascospores 22–26 × 10–12 μm; subpsoromic acid present; Solomon Islands ... ... C. hilli (A.W. Archer) A.W. Archer
Ascospores 14–18 × 6–7 μm; protocetraric acid present; South America ... ... C. inspersa Staiger
We are grateful to the Department of Science and Technology, Government of India, New Delhi, for their financial support.
