Introduction
The lichen genus Carbacanthographis Staiger & Kalb comprises 21 species world wide (Staiger Reference Staiger2002; Kalb Reference Kalb2004; Archer Reference Archer2006, Reference Archer2007, Reference Archer2009; Lücking et al. Reference Lücking, Archer and Aptroot2009; Bungartz et al. Reference Bungartz, Lücking and Aptroot2010; Sharma et al. Reference Sharma, Khadilkar and Makhija2010; Tripp et al. Reference Tripp, Lendemer and Lendemer2010). The genus is 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.
The closely allied genus Acanthothecis Clem. also has warty periphysoids, but can easily be distinguished from Carbacanthographis by a non-carbonized exciple. Carbacanthographis is morphologically similar to Graphis Adans., in having a well-developed, carbonized, convergent exciple; however, Graphis differs from Carbacanthographis in lacking periphysoids and in the strongly I+ ascospores.
In our earlier paper on this genus (Sharma et al. Reference Sharma, Khadilkar and Makhija2010), we recognized two species from India, C. marcescens from Tamil Nadu, Kerala and the Andanman Islands and a sorediate species C. sorediata B. O. Sharma, Makhija & Khadilkar from Tamil Nadu. Further investigation of the lichen family Graphidaceae from India has revealed the occurrence of two new Carbacanthographis species, namely C. albolirellata and C. indica, which are described in the present paper. A table comparing the characters of all accepted species of Carbacanthographis is also given.
Materials and Methods
The study is based on the examination of herbarium specimens lodged 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 standardized methods (Culberson & Kristinsson Reference Culberson and Kristinsson1970; Culberson Reference Culberson1972; White & James Reference White and James1985) and the solvent systems toluene-dioxane-acetic acid (180:45:5) and toluene-ethyl acetate-formic acid (139:83:8). The specimens were examined under UV light (365 nm).
The Species
Carbacanthographis albolirellata B. O. Sharma & Khadilkar sp. nov
MycoBank No.: MB 561007
Sicut Carbacanthographis coccospora sed ascosporis majoribus differt.
Typus: India, Tamil Nadu, near Daisy Bank, Kodaikanal, 25 January 1975, P. G. Patwardhan & A. V. Prabhu, 75.365 (AMH—holotypus).
(Fig. 1A, C–E)
Fig. 1. Carbacanthographis species. A, C–E, C. albolirellata (holotype AMH); A, habitus; C, vertical section of the ascocarp; D, warty periphysoids; E, ascospores. B, F–H, C. indica (holotype AMH); B, habitus; F, vertical section of the ascocarp; G, warty periphysoids; H, ascocarps. Scales: A & B = 1 mm; C & F = 50 µm; D & E, G & H = 10 µm.
Thallus crustose, corticolous, epiphloeodal, yellowish brown, dull, rough, verrucose, cracked, delimited by a thin, black hypothallus.
Ascocarps lirellate, black, white-pruinose, black underneath, prominent to sessile, simple, straight to slightly curved, 1–4 mm long with rounded ends. Disc slit-like, epruinose. Proper exciple convergent, completely carbonized including the base. Epithecium absent. Hymenium hyaline, not inspersed, I−, 75–150 µm high. Paraphyses simple. Periphysoids short, distinctly warty. Asci 8-spored; ascospores hyaline, submuriform, with 6–8 transverse and 1–2 longitudinal septa per segment, 16–20 × 6–8 µm, I+ blue violet.
Chemistry. No lichen substances detected.
Remarks. Carbacanthographis albolirellata is comparable to C. coccospora (Aptroot) Aptroot & Lücking, having similar morphological features, but C. coccospora has small, (6–) 9–12 × 7–10 µm long, ascospores.
Other species of Carbacanthographis which share similar morphological characters are C. amicta (Nyl.) Staiger & Kalb, C. crassa (Müll. Arg.) Staiger & Kalb, C. hilli (A. W. Archer) A. W. Archer, C. inspersa Staiger, C. muriformis E. A. Tripp & Lendemer, C. salazinica (A. W. Archer) A. W. Archer and C. subalbotecta Staiger & Kalb, but all of them differ in their chemistry.
Carbacanthographis albolirellata is differentiated from C. indica described below in having a completely carbonized exciple, submuriform ascospores and no lichen substances in the thallus.
The new species Carbacanthographis albolirellata has been collected only twice from Tamil Nadu in the Western Ghats of India. These mountains play a special role in the botany of the Indian subcontinent for their interesting flora and they are one of the richest lichen sites in India.
Additional specimen examined. India: Tamil Nadu: near Daisy Bank, Kodaikanal, 1975, P. G. Patwardhan & A. V. Prabhu, 75.367 (AMH).
Carbacanthographis indica B. O. Sharma & Khadilkar sp. nov
MycoBank No.: MB 561008
Sicut Carbacanthographis marscescens sed ascosporis trans-septatis differt.
Typus: India, Meghalaya, Garo hills, Lagerstroemia forest, 5 November 1977, P. G. Patwardhan & M. B. Nagarkar, 77.1340 (AMH—holotypus).
(Fig. 1B, F–H)
Thallus crustose, corticolous, epiphloeodal, greyish white, flat, smooth to rough, cracked, delimited by a black hypothallus.
Ascocarps lirellate, conspicuous, concolorous with the thallus, with a conspicuous, raised thalline margin, rarely simple, mostly irregularly branched, erumpent, 1–5 mm long, ends acute. Disc slit-like, epruinose. Proper exciple convergent, entire, laterally carbonized, base distinctly orange-brown. Epithecium absent. Hymenium hyaline, not inspersed, I−, 87–137 µm high. Paraphyses simple. Periphysoids short, indistinctly warty. Asci 8-spored; ascospores hyaline, trans-septate, with 10–15 transverse septa, 25–70 × 7·5–10 µm, I+ colour reaction weak.
Chemistry. Salazinic acid present.
Remarks. The only species so far known to have salazinic acid and a laterally carbonized exciple, Carbacanthographis marcescens (Fée) Staiger & Kalb, differs from the new species in having smaller, muriform ascospores. Similarly C. cleitops (Fée) Lücking and C. triphoroides (M. Wirth & Hale) Lücking have stictic acid and muriform ascospores.
Carbacanthographis indica is differentiated from species of Carbacanthographis with laterally carbonized exciples and trans-septate ascospores by the presence of salazinic acid. Carbacanthographis induta (Müll. Arg.) Lücking from Vietnam and C. iriomotensis (M. Nakan.) M. Nakan. & Kashiw. from Japan, have similar morphological characters but differ in their chemistry; C. induta has norstictic acid and C. iriomotensis has stictic acid.
Graphis garoana Nagarkar & Patw., a species from Meghalaya, India, clearly belongs to Carbacanthographis [holotype—India, Meghalaya, Garo hills, Darugiri reserve forest; 6 Dec, 1978, M. B. Nagarkar, 78.387–AMH (!)], and appears to be somewhat close to C. indica, sharing some characters such as a laterally carbonized exciple and trans-septate ascospores. However, G. garoana has simple, emergent, long lirellae up to 8 mm long, and has norstictic acid in addition to salazinic acid in the thallus.
Table 1. Comparison of characters of the accepted species of Carbacanthographis
Carbacanthographis indica can also be distinguished from the species of Carbacanthographis with completely carbonized exciples and trans-septate ascospores by the presence of salazinic acid and ascospore size. Carbacanthographis alloafzelii (A. W. Archer) A. W. Archer has psoromic acid and ascospores 18–20 × 8–10 µm. Carbacanthographis candidata (Nyl.) Staiger and C. chionophora (Redinger) Staiger & Kalb have protocetraric and lichexanthone in the thallus, while C. stictica Staiger & Kalb has the stictic acid complex.
Carbacanthographis indica has been collected from Meghalaya in North-East India, which is extremely rich in floral and faunal biodiversity, with several endemic species of lichens.
Additional specimens examined. India: North-East India: Meghalaya, Garo hills, Lagerstroemia forest, 1977, P. G. Patwardhan & M. B. Nagarkar, 77.2094, 77.2093 (AMH).
A comparison of the characters of the accepted species of Carbacanthographis is provided in Table 1.
We are grateful to the Department of Science and Technology, Government of India, New Delhi, for their financial support.
