MYCOTAXON. Volume 98, pp October December S. Nayaka & D.K. Upreti*

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1 MYCOTAXON Volume 98, pp October December 2006 Chroodiscus himalayanus, a new species from India S. Nayaka & D.K. Upreti* *upretidk@rediffmail.com Lichenology Laboratory, National Botanical Research Institute Rana Pratap Marg, Lucknow , India Abstract Chroodiscus himalayanus is described as new to science. The new species has transversely septate, acicular ascospores with a bead-like end cell. Key words Thelotremataceae, chroodiscoid, crustose lichen Introduction India has a rich diversity of thelotremataceous lichens distributed in tropical forests, especially in the Western Ghats region of south India. About 180 species of common thelotremataceous lichens, belonging to the genera Myriotrema, Ocellularia and Thelotrema, are known from the Indian subcontinent (Awasthi 2000). Sethy & Patwardhan (1987) and Singh (1979) described two foliicolous species of Chroodiscus from the Andaman and Nicobar Islands. One of our recent collections from Himalayas proved to be an interesting species of corticolous Chroodiscus, which is described here as new to science. Materials and methods The specimens were examined morphologically, anatomically and chemically. Thin hand-cut sections of apothecia and thallus were mounted in plain water, cotton blue, 5% KOH and iodine solution and observed under a compound microscope. For chemical spot tests the usual reagents of K, C and PD were used. TLC was performed in solvent system A following Walker & James (1990). Chroodiscus himalayanus Nayaka & Upreti, sp. nov. Fig. 1-5 Mycobank # MB Thallus typice corticola, tenuissimus vel evanescens, plerumque circa apothecia plus minusque restrictus, cinereo-viridis vel olivaceo-viridis, haud limitatus, ecorticatus, prothallo nullo, algis ad generam Trentepholiam pertinentibus, in parte basali thalli sitis. Apothecia dispersa, primum in thallo immersa, demum erumpentia, orbicularia,

2 Nayaka & Upreti mm lata, adnata vel basim constricta; disco plano, aurantiaco brunneis, laevis, nitido, epruinoso, plus minusque aperto, margin albido, 2 5 lobulato. Excipulum proprium hyalinum, ad basim dimidium, grandis crystalliferum; periphysibus parvis, distinctis. Epihymenium hyalinum vel luteolum, I+ caerulescens, deinde vinascens. Hymenium hyalinum, µm crassum, oleoso-inspersum, I+ caerulescens, deinde vinascens. Subhymenium et hypothecium hyalinum, oleoso-inspersum, I+ caerulescens, deinde vinascens. Asci 2 3 spori, cylindrici, 85 95( 110) logi et 8 10 µm lati, parietis, K, I, at lumine I+ pallide lutescente vel aurantiascente. Ascosporae hyalinae, non-halonatae, 40 78( 85) longae et 3 5 µm latae, septis transversalibus ad ( 30), aciculares, extremis cellulis moniliformis, I+ pallide lutescentes usque ad aurantiaco-lutescentes. Paraphyses simplices, tenues, cohaerentes, K, at I+ caerulescentes, deinde vinascentes. Etymology: From the Himalayas, referring to the type locality. Holotypus: INDIA, Himachal Pradesh, Kullu district, Great Himalayan National Park, Sainj Wildlife Sanctuary, Shakti, 2200 m, on bark, , R. Srivastava (LWG holotype). Thallus corticolous, crustose, thin to evanescent, ecorticated, smooth, rather patchy, usually restricted to around the apothecia, grey-green to olive-green, not delimited; photobiont Trentepholia, occurring in the basal part of thallus; prothallus absent. Ascomata apothecia, scattered, rarely 2 3 confluent, at first ± immersed in the thallus, soon emerging through irregular cracks, roundish, mm in diam., adnate, constricted at the base when mature; disc plane to concave, orange-brown, smooth, shiny, epruinose, usually completely exposed; margin whitish, 2 5 lobate, mm thick, in older apothecia exfoliating, developing radial fissures and dividing into 2 3 lamellae. Proper exciple in section hyaline, densely inspersed with calcium oxalate crystals, dimidiate at base, K, I, sometimes in mature apothecia forming with a supportive layer of bark cells; periphyses distinct; epihymenium hyaline to slightly yellowish, K, I+ blue turning wine red; hymenium hyaline, µm high, K, I+ blue turning wine red, inspersed with oil globules; subhymenium and hypothecium hyaline, inspersed with oil globules, K, I+ blue turning wine red. Asci 2 3 spored, cylindrical, 85-95( 110) x 8 10 µm, K, I or I+ with contents turning yellow to yellowish orange; ascospores hyaline, non-halonate, transversely 15 25( 30) septate, acicular, with basal end cell rounded, 40 78(85) x 3 5 µm, K, I+ yellow to golden yellow; paraphyses, mostly simple, coherent, K, I+ blue turning wine red. Chemistry: Thallus K, C, KC, P. No lichen substances in TLC. Distribution and ecology: At present C. himalayanus is known only from its type locality, in the north Himalayas, where it is found growing luxuriantly on tree trunks at an altitude of 2200 m. Remarks: C. himalayanus is characterized by chroodiscoid apothecia with a prominent white, exfoliating margin, transversely septate, acicular ascospores,

3 Chroodiscus Figure 1-5. Chroodiscus himalayanus (from holotype): 1. Habit; 2. L.S. of apothecia showing calcium oxalate crystals in exciple; 3. Bead like end cell; 4. Ascus; 5. Ascospores (Bars, Fig. 1 = 2 mm, 2 = 0.25 mm, 3&5 = 5 µm, 4 = 10 µm). the presence of calcium oxalate crystals in the exciple and oil globules in the hymenium. The ascospores are broader at one end and narrow gradually towards the other. The terminal cell at the broader end becomes swollen and bead-like in appearance. The hymenium exhibits a peculiar reaction with iodine by gradually turning from blue to wine red, while the asci and ascospores remain yellow to yellowish orange and yellow to golden respectively. Such a character is unique for the genus though the colour changes in the immature ascus contents or ascospores are observed (Kantvilas & Vězda 2000). Among the recognized corticolous Chroodiscus species, C. himalayanus is close to C. minor Kantvilas & Vězda, in having transversely septate ascospores, and a similar thallus and apothecial morphology. However, C. minor differs by its smaller apothecia ( mm wide) and transversely up to 7-septate, ellipsoid to fusiform ascospores. The other corticolous Chroodiscus taxa have muriform ascospores (Kantvilas & Vězda 2000). According to the new generic classification of the Thelotremataceae (Frisch 2006, Frisch & Kalb 2006) the genus Chroodiscus is now restricted to the foliicolous species, being characterised by a non-periphysate proper

4 Nayaka & Upreti exciple, truly thin-walled (without any, though faint, lateral thickenings of the septa), small, hyaline, I ascospores, a low hymenium and rather easily separated paraphyses. Another (monotypic) genus with thin-walled, hyaline, I ascospores, Acanthotrema Frisch (A. brasilianum (Hale) Frisch) differs by the presence of periphysoids (with spiny tips) and rigid, rather strongly agglutinated paraphyses with spiny end-cells. This species is corticolous. The third genus with chroodiscoid apothecia, Chapsa A. Massal., in the present circumscription appears to be still heterogeneous. It accommodates all corticolous species with thick-walled (though sometimes very indistinct) ascospores (hyaline or brown, I+ or I-), a rather rigid type of the paraphyses often with moniliform or branched tips, and periphysoids (sometimes indistinct). This genus largely complies with Thelotrema subgen. Asteristion of Matsumoto (2000). However, the new species described here seems not to fit in any of these genera. From Chroodiscus and Acanthotrema it differs in the large, acicular ascospores, which are of a reduced thick-walled type, and from Chroodiscus, additionally by the presence of periphysoids. It differs from Chapsa species in having large, acicular ascospores, the large number of crystals in the lateral proper exciple, which is rare in chroodiscoid species of Thelotremataceae or in any of the other species with periphysoids and the hymenium turning blue to wine red in iodine. The colour change in hymenial matrix is also rare in species of the Thelotremataceae. Some characters of C. himalayanus like the large, rather thinwalled acicular ascospores, the large number of crystals in the lateral proper exciple and the hymenium turning blue to wine red in iodine even hint on a possible relationship with the Stictidaceae (Sherwood 1977). The taxonomy of the chroodiscoid Thelotremataceae is still not finally settled and further changes in the delimitation of genera (including the description of additional new genera) are to be expected (personal communication, A. Frisch). However, following the old taxonomy and considering the taxonomic difficulties outlined above, C. himalayanus is described as a new species here. Acknowledgements We are thankful to the Director, National Botanical Research Institute, Lucknow for providing necessary laboratory facility to work, to Ministry of Environment and Forests, New Delhi for financial support, to Dr. P.K. Divakar, Mr. Yogesh Joshi for their valuable suggestions, to Mr. Rajesh Bapai for assisting in TLC, to Drs. Gintaras Kantvilas and Andreas Frisch for their useful comments. Literature Cited Awasthi DD A key to the microlichens of India, Nepal and Sri Lanka. Biblioth. Lichenol. 40: Awasthi DD Lichenology in Indian Subcontinent. Bishen Singh Mahendra Pal Singh, Dehra Dun, India.

5 Chroodiscus Frisch A, Kalb K A monograph of Thelotremataceae with a complex structure of the columella. Biblioth. Lichenol. 92: Frisch A The lichen family Thelotremataceae in Africa. Contributions towards a new systematics of the lichen family Thelotremataceae. Biblioth. Lichenol. 92: Kantvilas G, Vězda A Studies on the lichen family Thelotremataceae in Tasmania. The genus Chroodiscus and its relatives. Lichenologist 32(4): Matsumoto T Taxonomic studies of the Thelotremataceae (Graphidales, lichenized Ascomycota) in Japan (1) Genus Thelotrema. Journ. Hattori Bot. Lab. 88: Sethy PK, Patwardhan PG Some foliicolous lichens from Nicobar and Andaman Islands, India. Biovigyanam 13: Sherwood MA The Ostropalean fungi. Mycotaxon 5: Singh A The lichen flora of India with special reference to Andaman Islands , in TN Khushoo, PKK Nair (eds.), Progress in Plant Research. Silver Jubilee Publication, National Botanical Research Institute, Lucknow, India. Walker FJ, James PW A revised guide to microchemical techniques for the identification of lichen products. Bull. Brit. Lich. Soc. 46:

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