A New Species of Schaereria (Lichenized Fungi) from the Falkland Islands

Transcription

1 The Bryologist 104(1), pp Copyright 2001 by the American Bryological and Lichenological Society, Inc. A New Species of Schaereria (Lichenized Fungi) from the Falkland Islands ALAN M. FRYDAY Herbarium, Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824, U.S.A. RALPH S. COMMON Division of Human Pathology, Michigan State University, East Lansing, MI 48824, U.S.A. Abstract. The new species, Schaereria porpidioides, is described from collections made by H. A. Imshaug & R. C. Harris from the Falkland Islands in The systematic position of Schaereria, with respect to its relationship to Trapelia, is discussed. In 1968, the U.S. Antarctic Research Program financed an expedition to the Falkland Islands (Islas Malvinas) that included the lichenologists H. A. Imshaug and R. C. Harris. They made 2,738 lichen collections (with many duplicates) and produced a preliminary report in which they estimated a total lichen flora of about 235 species (Imshaug 1969) although these were not listed. Some specimens were accessioned into the Michigan State University Herbarium (MSC), but the bulk of their collections received only a preliminary examination and remained in temporary storage in cardboard boxes. The U.S. National Science Foundation recently awarded Michigan State University a grant to re-activate the MSC lichen collection that has facilitated access to this extensive resource which also includes collections from Patagonia, the Juan Fernandez Islands (Chile), Campbell and Auckland Islands (New Zealand), and Kerguelen Island. Henry Imshaug and his students sorted many of these collections to genus, or even species, but these need to be re-assessed in light of taxonomic advances made over the intervening 30 yr. Among these is the crustose taxon described here as Schaereria porpidioides. MATERIALS AND METHODS The thallus and apothecial characteristics of the specimens were examined by light microscopy on hand-cut sections mounted in water and 10% KOH. The ascus structure was studied in 0.15% aqueous IKI without prior treatment and after pretreatment with 10% KOH. Detailed anatomical investigation was made of pre-bleached sections using the reagents and methods detailed in Common (1991). Specimens of Schaereria cinereorufa (Schaerer) Th. Fr., S. fuscocinerea (Nyl.) Clauzade & Roux, Trapelia coarctata (Sm.) M. Choisy, and T. mooreana (Carroll) P. James also held in MSC were studied by the same methods. SCHAERERIA PORPIDIOIDES Fryday & Common, sp. nov. Thallus effusus, endolithicus, medulla amyloidea. Apothecia superficiales, basi constricta, (0.8) (2.0) mm diametro. Epihymenium brunneum. Ascosporae late ellipsoideae vel subgloboseae, m. Thallus effuse, immersed, rarely visible between grains of substratum (coarse sandstone), when visible creamy-white, without well developed cortex, a few brown pigmented cortical cells sometimes visible in microscopic section; usually covering relatively large areas (to cm diam.). Medulla weakly IKI blue to red-purple. Photobiont chlorococcoid, cells (9 )12 15( 18) m diam. Apothecia scattered, black or dark brown, lecideine, superficial, strongly constricted at base, (0.8 ) ( 2.0) mm diam., flexuose when mature; disc flat, usually white pruinose, more so when young, black or slightly brownish, brown when wet; proper exciple black, persistent and slightly raised, 0.1 mm wide (Fig. 1). Hymenium hyaline, m tall (Fig. 2); epihymenium brown, m wide. Paraphyses m thick swelling at apex to 5.0 m, with brown pigmented cap; simple, occasionally branched towards apex, septate, becoming moniliform toward apex, readily separating in water (Fig. 3), IKI very pale purple. Asci cylindric, ca m, outer walls IKI blue, contents IKI red-brown, without tholus, Schaereria-type (Fig. 4), dehiscing by simple split in outer wall (Fig. 5). Ascospores hyaline, 8/ascus, uniseriate in ascus, broadly ellipsoid to sub-globose (14.0 ) ( 20.0) (8.5 ) ( 13.5) m, length/breadth ratio Hypothecium composed of randomly arranged hyphae, hyaline above, becoming pale to mid-brown below, m high, merging into the darkbrown, horizontally arranged hyphae of excipulum that extends below hypothecium. Excipulum cupular, extending below hymenium and hypothecium as horizontally arranged, dark-brown pigmented hyphae (Fig. 2), m high; laterally with ca 100 m wide pale brown inner zone of radiating hyphae ca 3.5 m wide and dark brown outer zone /00/ $0.75/0

2 110 THE BRYOLOGIST [VOL. 104 FIGURES 1 2. Schaereria porpidioides (isotype, Imshaug & Harris BCRU) 1. Thallus and apothecia. Bar 2 mm. 2. Section of apothecium under polarized light showing crystals in exciple. Bar 200 m. ca 80 m wide composed of isodiametric cells 8 12 m across. Interspersed with large groups of crystals clearly visible under polarized light (Fig. 2). Conidiomata pycnidia, not frequent but usually present, black, immersed, mm wide, walls dark brown. Conidia simple, cylindric ca m, arising from elongate, simple, conidiogenous cells, Type II of Vobis (1980 Fig. 6).

3 2001] FRYDAY & COMMON: SCHAERERIA PORPIDIOIDES 111 FIGURES 3 6. Schaereria porpidioides (isotype, Imshaug & Harris BCRU) 3. Paraphyses and dehisced asci. Bar 50 m. 4. Intact ascus and ascospores. Bar 10 m. 5. Dehisced ascus. Bar 10 m. 6. Squash of pycnidium showing pycnidia and conidiogenous cells. Bar 10 m.

4 112 THE BRYOLOGIST [VOL. 104 FIGURE 7. Known distribution of Schaereria porpidioides on map of Falkland Islands. Chemistry: Thallus and apothecia C, K, KC, Pd ; unidentified fatty acid detected by TLC. Nomenclature and etymology. The specimens in MSC are annotated Trapelia? brunnea, however, the asci of the new species completely lack a tholus and are clearly of the Schaereria-type. Other anatomical characters (e.g., paraphyses, condia) also indicate a placement in Schaereria. The epithet brunnea, presumably refers to the brown pigmentation of the exciple, hypothecium, and epihymenium. Although species of Schaereria are usually considered to have a blue-green epihymenium, the two recently described southern hemisphere species, S. xerophila H. Mayrhofer & Rambold and S. bullata Kantvilas, also both have a brown pigmented epihymenium (Kantvilas 1999; Rambold 1989). Thus brunnea is not indicative of a good distinguishing character for the species. The epithet porpidioides refers to the gross morphology of the species, which is that of a member of the genus Porpidia e.g., P. macrocarpa (DC.) Hertel & Schwab, and is not intended to indicate any close systematic relationship to that genus. Distribution and ecology. Schaereria porpidioides is known only from the collections made by Imshaug and Harris in 1968 from the Falkland Islands (Fig. 7). From the collection details it appears to be a species of exposed siliceous rocks. No vascular plants or bryophytes are present in the specimens and associated lichen species are few, but include Neuropogon fasciata (Du Rietz) Lamb, Pertusaria spegazzinii Müll. Arg., Poeltidea perusta (Nyl.) Hertel & Hafellner, and Rhizocarpon geographicum (L.) DC. TYPE: FALKLAND ISLANDS. West Falkland, Mt Adam, UTM Grid 21F TC 8781, m, feldmark on summit ridge, 25 January 1968, H. A. Imshaug & R. C. Harris (MSC, holotype; BCRU, E, HO, M, UPS, isotypes). Paratypes. FALKLAND ISLANDS. East Falkland, Mt Usborne, Imshaug 39961, 39992, 39995, 40027, 40052, & Harris (BM, ESS, H, MSC, OTA); Stanley, Mt Kent, Imshaug & Harris (CANB, MSC); Mt Harriet, Imshaug & Harris (FH, MSC). West Falkland, Hill Cove, West French Peak, Imshaug & Harris (MSC); Mt Adam, Imshaug & Harris (MSC); Port Howard, Imshaug & Harris (MSC, VALPL); Fox Bay, Imshaug & Harris (CANL, MSC). Other specimens examined. Schaereria cinereorufa: Norrlin, Herb. Lich. Fenn. 191 (as Lecidea lugubris Smrf., Nyl.), Norrlin (MSC). Sweden, Bohuslän, Magnusson 9877 (MSC). Schaereria fuscocinerea: SWEDEN. UPPLAND. Santesson (MSC). U.S.A. COLORADO. Anderson 9366 & E.R. Anderson (MSC). Trapelia coarctata: U.S.A. MICHIGAN. Knutson 1 (MSC). Trapelia mooreana: NOR- WAY. Steinsaethorgen, 28 vii 1950, Havaas (MSC). DISCUSSION With the addition of the new species, the genus Schaereria now consists of eight species. Most occur on siliceous rocks, although two Northern Hemisphere species, S. corticola Tønsberg and S. parasemella (Nyl.) Lumbsch (syn. Hafellnera parasemella (Nyl.) Haumeau & Roux), are corticolous and lichenicolous, respectively (Kantvilas 1999). Of the saxicolous species, S. cinereorufa and S. fabispora Hertel & Zurn have only been recorded from the Northern Hemisphere; S. fuscocinerea is bipolar, and S. bullata, S. porpidioides, and S. xerophila are apparently confined to the Southern Hemisphere.

5 2001] FRYDAY & COMMON: SCHAERERIA PORPIDIOIDES 113 Schaereria porpidioides differs from all other described saxicolous species of Schaereria in lacking a well-developed thallus only the Northern Hemisphere, non-saxicolous S. corticola and S. parasemella have this character. Lumbsch (1997) considered including S. corticola in the monotypic genus Hafellnera Haumeau & Roux on account of its thin thallus, epiphytic habit, and halonate ascospores, but concluded that these characters were not sufficient to justify separation at the generic level and, conversely, included Hafellnera within the synonymy of Schaereria. It is possible that the endolithic thallus of S. porpidioides is an environmental modification resulting from the extremely exposed conditions from which the species was collected, as the one collection from sheltered rocks (I see above) had a somewhat better developed thallus although still thin and without a well-developed cortex. The only other species of Schaereria known from the Southern Hemisphere are the recently described S. bullata and S. xerophila and the bipolar species S. fuscocinerea. Schaereria bullata and S. xerophila are currently known from only continental Tasmania and Australia, respectively whereas S. fuscocinerea is known form South Georgia (Hertel 1984), New Zealand (Hertel 1989), and Australia (Rambold 1989). The three exclusively Southern Hemisphere species all have only brown pigment in the epihymenium whereas in the Northern Hemisphere species a green-blue pigment is always present. Two further collections from the Southern Hemisphere, both with a brown epihymenium, are also referable to Schaereria. A collection from Kerguelen (Poulsen 182a, C) resembles S. porpidioides in having sessile apothecia, but has globose ascospores (12 14 m diam.), a less well-developed excipulum, and apothecia with a brown, epruinose disc with pruinose margin. A further collection from Victoria, Australia (Elix 40440, MSC distributed as Protoparmelia badia) has an associated species that most closely resembles S. xerophila, but differs in having ellipsoid ascospores ( m), although these are poorly formed. It is possible that these collections are both referable to S. xerophila but, unfortunately, that species is known only from the type collection and more material is required to understand its infra-specific variation. Apothecia in most species of Schaereria rarely exceed 0.8 mm diam., although in S. cinereorufa and the related S. bullata they may reach 1.2 mm diam. The large (up to 2 mm across), flexuose apothecia of S. porpidioides are unique within the genus and immediately distinguish it from all other taxa. The apothecia have a close resemblance to those of Trapelia geochroa (Körber) Hertel and T. mooreana and it appears that molecular data places these two species closer to Schaereria than to Trapelia (H. T. Lumbsch, pers. comm.). Trapelia and Schaereria are both now included in the suborder Agyriineae (Lumbsch 1997) and Lunke et al. (1996) considered the Schaereria-type ascus structure derived from the Trapelia-type by reduction. As well as the different ascus structure, Trapelia also has narrower, branched, and anastomosing paraphyses without the swollen apex characteristic of Schaereria species. Although T. mooreana and T. geochroa differ from the type species of Trapelia (T. coarctata) in having a better developed excipulum composed of long-celled, pachydermatous hyphae (short-celled, thin-walled hyphae in T. coarctata) it is still different from the paraplectenchymatous excipulum present in Schaereria. Detailed examination of S. porpidioides and related taxa using a variety of staining methods (Common 1991) revealed some significant differences. All three species of Schaereria studied (S. cinereorufa, S. fuscocinerea and S. porpidioides) had a strong I blue amylomycan-type reaction (Common 1991) in the outer walls of asci and ascogenous hyphae in both 0.15% and 1.5% IKI, without pretreatment with KOH. In addition, a pale, diffuse bluish to red-purple reaction was seen in thallus and apothecial tissues of all three species. This reaction, which has staining characteristics similar to isolichenan, is best seen when sections are pre-bleached with C, stained with IKI, and then transferred to iodine-lactophenol (ILP). Similar, but much more intensely purple reactions were seen on scattered hyphae in the hypothecium in S. cinereorufa and S. porpidioides. A third reaction type, a purple reaction induced by pretreatment with concentrated nitric acid (followed by 1.5% IKI and transfer to ILP), was also present in ascocarp and thallus tissue of all three Schaereria species studied. In addition, an intense red-brown reaction was seen in the thallus and basal apothecial tissue in S. porpidioides in zinc-iodine (ZnIKI reagent). A similar reaction was seen in S. fuscocinerea, but not in S. cinereorufa. In contrast, no iodine reactions were detected with the same methods in thallus or apothecial tissue of Trapelia mooreana, including the asci, which were I even after pretreatment with KOH. The asci of Trapelia coarctata were I blue in 0.15% IKI but showed only reddish staining in 1.5% IKI. All other tissues of T. coarctata were I with all tests. These results provide additional characters that confirm a clear separation between Schaereria and Trapelia, at least in the species studied. They fail

6 114 THE BRYOLOGIST [VOL. 104 to confirm a link between Schaereria and T. mooreana, and suggest instead that there are significant differences in cell wall components between the two groups. Although the differences are likely to be taxonomically significant, further studies within the Agyriineae will be necessary in order to provide an adequate perspective. ACKNOWLEDGMENTS The National Science Foundation is thanked for financial assistance both to H. Imshaug, for his expedition to the Falkland Islands (under the Antarctic Research Program) and Award No. DBI (Alan Prather, PI) to Michigan State University that facilitated the authors access to Imshaug s collections. B. J. Coppins (E) kindly corrected the Latin diagnosis. LITERATURE CITED COMMON, R. S The distribution and taxonomic significance of Lichenen and Isolichenen in the Parmeliaceae (lichenized Ascomycotina), as determined by iodine reactions. I. Introduction and methods. II. The genus Alectoria and associated taxa. Mycotaxon 41: HERTEL, H Über saxicole lecideoide Flechten der Subantarktis. Beiheft Nova Hedwigia 79: New records of lecideoid lichens from the Southern Hemisphere. Mitteilungen der Botanischen Staatssammlung München 28: IMSHAUG, H. A Expedition to Falkland Islands Antarctic Journal of the United States 4 (5): KANTVILAS, G A new species of Schaereria from Tasmania. Lichenologist 31: LUMBSCH, H. T Systematic studies in the suborder Agyriineae (Lecanorales). Journal of the Hattori Botanical Laboratory 83: LUNKE, T., H. T. LUMBSCH & G. B. FEIGE Anatomical and ontogenetic studies on the lichen family Schaereriaceae (Agyriineae, Lecanorales). THE BRY- OLOGIST 99: RAMBOLD, G A monograph of the saxicolous, lecideoid lichens of Australia (excl. Tasmania). Bibliotheca Lichenologica 34: VOBIS, G Bau und Entwicklung der Flechten-Pycnidien und ihrer Conidien. Bibliotheca Lichenologica 14: ms. received May 8, 2000; accepted July 25, 2000.