Introduction
The lichen genus Graphis sensu Staiger (Reference Staiger2002) is one of the largest genera in the lichen family Graphidaceae, comprising over 300 taxa, and so far 54 species have been recorded throughout the world with an inspersed hymenium (Lücking et al. Reference Lücking, Archer and Aptroot2009). Graphis insulana (Müll. Arg.) Lücking & Sipman is the only species from India known to have an inspersed hymenium (Chitale et al. Reference Chitale, Makhija and Sharma2011).
The lichen genus Pallidogramme Staiger, Kalb & Lücking, a genus that was recently introduced to accommodate species previously placed in Hemithecium subgenus Leucogramma Staiger (Lücking et al. Reference Lücking, R, Chaves, Sipman, Umaña and Aptroot2008), includes seven species worldwide (Lücking et al. Reference Lücking, R, Chaves, Sipman, Umaña and Aptroot2008; Archer Reference Archer and McCarthy2009; Chitale et al. Reference Chitale, Makhija and Sharma2009), three of which have been recorded from India (Chitale et al. Reference Chitale, Makhija and Sharma2009). The genus is characterized by well-developed labia, a convergent, non-carbonized exciple that is mostly crenate and with internal striae, the disc not being visible, an inspersed hymenium, and pale brown to brown, I+ reddish brown ascospores.
During the course of our revisionary studies on the lichen family Graphidaceae, we have come across two interesting new species which belong to the lichen genera Graphis and Pallidogramme, and these are described here as Graphis parvicarpa and Pallidogramme bengalense, respectively.
Materials and Methods
Herbarium specimens collected from the South Western Ghats, Eastern Himalaya, Western Himalaya and the Andaman and Nicobar Islands of India by various lichenologists from Agharkar Research Institute and deposited in Ajrekar Mycological Herbarium (AMH) were analyzed. Hand-cut sections of thalli and ascomata were mounted in water and lactophenol cotton blue for examination. Thin-layer chromatography was carried out using standardized methods (Culberson & Kristinsson Reference Culberson and Kristinsson1970; Culberson Reference Culberson1972; White & James Reference White and James1985) with the solvent systems A (toluene-dioxane-acetic acid: 180:45:5) and G (toluene-ethyl acetate-formic acid: 139:83:8). The specimens were also examined under UV light (365 nm). Specimens of Graphis were identified using the world key of Graphis (Lücking et al. Reference Lücking, Archer and Aptroot2009) and by comparison with types and protologues. The specimens have been deposited in the Ajrekar Mycological Herbarium (AMH).
The Species
Graphis parvicarpa sp. nov
MycoBank No: MB 561698
Fig. 1. Graphis parvicarpa (holotype, AMH). A, habitus; C, vertical section of ascocarp; E, vertical section of ascocarp showing inspersion. Pallidogramme bengalense (holotype, AMH). B, habitus; D, vertical section of ascocarp; F, vertical section of ascocarp showing inspersion. Scales: A & B = 1 mm, C & D = 100 µm, E & F = 50 µm.
(Fig. 1 A, C, E)
Similis Graphis tenoreinsis, sed hymenio insperso et acidum norsticticum continens differt.
Typus: India, Karnataka, Chikkaballapur district, Nandi hills, 1 December 1999, U. V. Makhija, 99.360 (AMH—holotypus).
Thallus crustose, corticate, epiphloeodal, yellowish grey, highly cracked, glossy, uneven, delimited by a very thin, black hypothallus.
Ascomata lirelline, 1–3 mm long, 0·2–0·3 mm wide, simple to sparsely branched, concolorous with the thallus, prominent, terminally obtuse. Disc narrow, epruinose. Proper exciple 1–4-striate, apically carbonized, converging apically, with thick lateral thalline margin, bulging apically, studded with crystals. Hymenium hyaline, inspersed with small oil droplets that partially persists in KOH, I−. Paraphyses simple, brownish at apices. Asci 1–2-spored. Ascospores hyaline, muriform, 62–122 × 17–32 µm, I+ violet.
Chemistry. Norstictic acid present in the thallus.
Remarks. The new species Graphis paravicarpa is characterized by short, prominent lirellae, an apically carbonized, striate exciple, inspersed hymenium, 1–2-spored asci, muriform ascospores, and by the presence of norstictic acid.
Graphis tenoriensis Lücking & Chavas differs from G. parvicarpa in having no lichen acids in the thallus and a clear hymenium. Graphis nigroglauca Leight., a species with similar morphology, has trans-septate ascospores.
Graphis semirigida (Müll. Arg.) Lücking, with more or less similar characters in having a striate exciple, large, muriform ascospores and norstictic acid, however, has a clear hymenium. Graphis bipartita (Müll. Arg.) Lücking also shares similar morphological characters, but has prominent, elongate, irregularly branched lirellae and a clear hymenium.
Graphis insulana (Müll. Arg.) Lücking, with large, muriform ascospores, inspersed hymenium, and no lichen substances, differs from G. parvicarpa in having laterally carbonized entire labia.
Lücking et al. (Reference Lücking, Archer and Aptroot2009), in his world key to Graphis, has enumerated 20 groups for the identification of a large number of species of Graphis, based on characters such as exciple, hymenium and ascospore septation. So far no species has been recorded having the combination of striate labia with apical or lateral combination, inspersed hymenium and muriform ascospores, and apparently it seems that Graphis parvicarpa is the first known in the genus so far.
Although the degree of carbonization of the exciple is weak or irregular, it is always present at least in the apical part, thus avoiding confusion with species of Hemithecium which have a dark brown coloration in the apical region of the exciple. Hemithecium oryzaeformis (Fée) Staiger shares some morphological characters, especially the hyaline, muriform, large ascospores and presence of norstictic acid in the thallus; however, apart from the non-carbonized exciple, it has slightly short, oryzaeform lirellae 1–1·5 µm long, 1-spored asci and a clear hymenium.
The new species has been collected from the semi-evergreen forest area in the Western Ghats of India.
Additional specimens examined. India: Karnataka: Chikkaballapur district, Nandi hills, 1999, U. V. Makhija, 99.368 (AMH).
Pallidogramme bengalense sp. nov
MycoBank No: MB 561699
(Fig. 1 B, D, F)
Similis Pallidogramme commutabilis sed ascosporis minoribus differt.
Typus: India, West Bengal, Darjeeling district, Kurseong, c. 4864 ft., 14 November 1977, P. G. Patwardhan & M. B. Nagarkar, 77.1717 (AMH—holotypus).
Thallus crustose, corticate, epiphloeodal, blackish brown, glossy, cracked, smooth, surrounded by a thin, black hypothallus.
Ascomata lirelline, short to long, 0·5–7 mm long, 0·2–0·3 mm wide, creamish, simple to branched, striate, semi-emergent, terminally acute. Disc narrow, epruinose. Exciple striate, apically dark brown, convergent, covered with lateral thalline margin. Hymenium hyaline, inspersed with oil globules that partially dissolve in KOH. Paraphyses simple. Asci 8-spored. Ascospores initially hyaline but later turning pale brown, muriform, 50–80 ×12–20 µm, I+ blue.
Chemistry. No lichen substances present.
Remarks. Pallidogramme bengalense is a distinct taxon characterized by its striate exciple, muriform, hyaline to pale brown ascospores, inspersed hymenium, and no lichen substances.
The only other species lacking substances known in the genus, Pallidogramme commutabilis (Kremph.) Chitale & Makhija, differs from P. bengalense in having its ascomata more or less aggregated in diffuse patches on the thallus, an entire exciple, and large, broad ascospores, 66–126 × 21–30 µm. Pallidogramme bengalense is distinguished from other species of Pallidogramme by the absence of lichen acids: P. chapadana (Redinger) Staiger, Kalb & Lücking, P. chlorocarpoides (Nyl.) Staiger, Kalb & Lücking, P. chrysenteron (Mont.) Staiger, Kalb & Lücking, P. indica Dube & Makhija, and P. montiscalvi (A. W. Archer) A. W. Archer, all have stictic acid and satellite substances.
Pallidogramme bengalense was collected in subtropical forest regions of Darjeeling.
Additional specimens examined. India: West Bengal: Darjeeling district, Kurseong, c. 4864 ft., 1977, P. G. Patwardhan, & M. B. Nagarkar, 77.1698, 77.1699, 77.1703, 77.1715 (AMH).
We are grateful to the Department of Science and Technology, Government of India, New Delhi, for their financial support.
