Lecania Croatica (Syn
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Opuscula Philolichenum, 8: 41-49. 2010. A review of Lecania croatica (syn. Catillaria croatica) in North America 1 2 RICHARD C. HARRIS & JAMES C. LENDEMER ABSTRACT. – The status of Lecania croatica in North America is reviewed. Although originally reported only from Great Smoky Mountains National Park, the species is shown to be widespread and locally common throughout the Appalachian Mountains as well as Great Lakes Region and Ozark Ecoregion of eastern North America. Both American and European material of the species is illustrated for the first time and a map of the distribution in North America is provided. INTRODUCTION The last two decades have seen a remarkable increase in our knowledge of isidiate and sorediate crustose lichens both in North America and abroad. Indeed from our continent alone numerous species have been, and continue to be, newly described and reported (Fryday et al. 2007; Harris & Ladd 2008; Harris & Lendemer 2009; Kalb 2004, Lendemer 2007, 2009, 2009a; Lendemer et al. 2008; Lendemer & Harris 2007; Lendemer & Lumbsch 2008; Printzen & Tønsberg 2007, Tønsberg 2004, 2007; Wetmore 2004). Despite the amount of progress it is clear from our studies in the field and in the herbarium that there are still many unresolved problems. Among these is a puzzling corticolous sorediate taxon that lacks secondary chemistry and is common throughout eastern North America. The first author initially became aware of this species more than four decades ago while collecting in northern Michigan and included it as “Lecidea sp. 4” in his keys to the lichens of the Michigan Straits Region (Harris 1977). In the decades following this publication many additional specimens of the taxon accumulated, and when the second author began collecting in North America he also routinely encountered it. In light of copious material available to us, which included fertile specimens, we decided to finally pursue the identity of this taxon and describe it if it was new to science. While reviewing the literature for other sorediate crustose lichens without lichen substances we came upon the name Lecania croatica (Zahlbr.) Kotlov (syn. Catillaria croatica Zahlbr.). The species had been tentatively referred to Cliostomum Fr. by Printzen (1995) in the excludenda of his monograph of Biatora and had been casually reported from Great Smoky Mountains of eastern North America by Tønsberg (2004). Comparison of our material to a topotype of C. croatica, as well as to several North American specimens identified by Christian Printzen, convinced us that, at least until we have a better understanding of the European population, the name Lecania croatica can be applied to the American population. Since our material significantly extends the range of L. croatica in North America we have chosen to provide a review of the species and take the opportunity to provide a detailed description as well as the first color illustrations of both European and North American material. MATERIALS AND METHODS Specimens were studied with a Zeiss Stemi 200-C dissection microscope and images of the thallus and apothecia were captured using an Olympus DP20 digital camera using Microsuite Special Edition. Microscopic characters were measured in water with an Olympus BX51 microscope and images were 1 RICHARD C. HARRIS — Institute of Systematic Botany, The New York Botanical Garden, Bronx, NY 10458-5126, U.S.A. – e–mail: [email protected] 2 JAMES C. LENDEMER — Institute of Systematic Botany, The New York Botanical Garden, Bronx, NY 10458-5126, U.S.A. U.S.A. – e–mail: [email protected] 41 captured in the same manner as above. The chemistry of representative specimens of all species was studied with Thin Layer Chromatography (TLC) using solvents A or C following standardized methods. A representative specimen of Lecania croatica was also examined with SEM to better characterize the ontogeny of the soralia. Samples were removed from a herbarium specimen with a razor blade and not subjected to fixation, rinsing, or dehydration. They were mounted on aluminum stubs using conductive carbon adhesive tabs and sputter coated for 2 minutes at 10 milliamps with gold. Following coating the samples were examined with a scanning electron microscope (Hitachi S-2700) with a tungsten filament operating with an accelerating voltage of 20 kv. Digital images were captured using Quartz PCR Image Management System. THE SPECIES Lecania croatica (Zahlbr.) Kotlov, Nov. sist. Niz. Rast. 37:251. 2004. Catillaria croatica Zahlbr., Ann. Mycol. 4: 487. 1906. TYPE: “Kroatien: An dem Wege von Jelenje [gornje] auf den Risnjak [?] in der Nähe [des Berges] Levurdica, [1000-1200 m], an Bergahorn, 1904, [J. Schuler]” (W, lectotype designated by Printzen, 1995). DESCRIPTION (AMERICAN SPECIMENS). – Thallus superficial, ranging from well developed to poorly developed and even mostly immersed, light gray or tan, rarely dark green, areolate when well developed, 50-70 µm thick; areoles sometimes coalescing and ± continuous, sometimes reduced to small indistinct bumps or mostly immersed, when well developed with a poorly developed, patchy cortex, sorediate, with discrete rounded soralia; soralia flat, convex or weakly capitate, scattered to crowded, sometimes crowded and appearing patchily leprose, initially formed at margins of areoles (always?), 0.2-0.4 mm across; soredia pale green when fresh, slightly yellowish or rarely whitish in herbarium, globose, 12-15 µm across, aggregates to ca. 30 µm; photobiont green, globose, 6-10 µm across. Apothecia initially with pale brown or pale orangish disk and pallid margin, aging to medium brown disk with margin concolorous or slightly paler, often ± mottled, entirely dark brown in exposed situations (once almost black), sessile, weakly concave, flat or weakly convex, constricted at base, 0.2-0.4(-0.7) mm across, 0.15-0.25 µm high; margin level with disk, persistent or not visible in more swollen apothecia. Exciple usually patchily brown tinted, especially adjacent to hymenium, occasionally entirely brown, occasionally completely colorless, 60-80 µm thick, composed of thick-walled radiating hyphae. Hypothecium colorless or tinted pale brown, ca. 50-60 µm thick. Epihymenium colorless. Hymenium colorless above, tinted brown in lower part (once almost entirely brown), 70 µm high. Paraphyses more or less unbranched, ca. 2.2-2.4 µm across, slightly expanded at tips to 3-3.5(-5) µm. Asci Bacidia type with shallow axial body, with 8 irregularly arranged or ± biseriate spores. Ascospores variable, narrowly fusiform to fusiform, colorless, 0-1-[2]-septate, 12-15(-17) x 3-4(-4.5) µm. Pycnidia immersed, subglobose, brown at apex, colorless below, ca. 70-100 µm across. Conidia filiform, 13-19 x 1 µm. CHEMISTRY. – No substances detected. Spot tests: K-, C-, KC-, P-, UV-. Brown apothecial pigment K-, N+ red purple, fading. Hymenium I+ mixture of blue green and dirty orangish, KI+ dark blue green. Hypothecium weakly I+ blue-green in upper part, patchily KI+ blue-green. ECOLOGY AND DISTRIBUTION. – In North America Lecania croatica occurs on the bark of hardwoods primarily in high humidity. We examined only a single collection from a conifer (Tsuga). Occasionally the Lecania grows off bark onto bryophytes. The species is infrequent but often locally abundant and is widespread in the Appalachian Mountains with disjunct populations in the Great Lakes Region and Ozark Ecoregion. It only occasionally produces apothecia (10/50), often only sparingly, i.e., one or two per collection. DISCUSSION. – We are adopting the name Lecania croatica for this taxon with a little hesitation for two reasons. First, we have examined only a single European specimen and there is only a single previous description available (the original protologue) although Hafellner et al. (2005) discuss the separation from Mycobilimbia epixanthoides (Nyl) Hafellner & Türk. Reports in the literature are few, Austria (Hafellner et al. 2005), Croatia (Zahlbruckner 1906), Romania (Ciurchea undated), Slovakia (Reese Naesborg et al. 2007), Slovenia (Mrak et al. 2004). American material agrees with Zahlbruckner’s in appearance of the soralia (yellowish in herbarium, “lutescentibus” according to Zahlbruckner, 1906), structure of exciple, and 42 Plate 1. European material of Lecania croatica (all from Zahlbr. Lich. Rar. 81, FH). Figures 1-2, thallus and apothecia (scale = 1.0 mm). Figure 3, section of apothecium (scale = 100 µm). Figure 4, asci (scale = 20 µm). Figure 5, ascospores and asci (scale = 20 µm). Figure 6, conidia (scale = 20 µm). 43 Plate 2. North American material of Lecania croatica. Figure 1, soralia and apothecia (Buck 41693, scale = 1.0 mm). Figure 2, marginal soralia (Buck 41693, scale = 1.0 mm). Figure 3, section of apothecium (Buck 41640, scale = 200 µm). Figure 4, exciple (Buck 41640, scale = 50 µm). Figure 5, asci (Lendemer 16530, scale = 20 µm). Figure 6, conidia (Buck 41640, scale = 20 µm). Figure 7, ascospores (Lendemer 16530, scale = 20 µm). 44 Plate 3. North American material and distribution map of Lecania croatica. Figures 1-2, soredia stained with phloxine (left) and in water (right) (Buck 41640, scale = 20 µm). Figure 3, geographic distribution of L. croatica in North America as presently known based on specimens at CANL and NY. Figure 4, section of pycnidium (Buck 41640, scale = 50 µm). Figures 5-6, gross morphology of soralia in final stage of development (Harris 8815 & Harris 9297, scales = 1 mm and 0.5 mm respectively). 45 Plate 4. Scanning electron micrographs of Lecania croatica (all from Buck 41649). Figure 1, gross morphology of thallus and soralia. Figure 2, detail of the soredia. Figures 3-5, ontogeny of soralia: initiating marginally on an areole, expanding over the surface of the areole, and eventually forming a large discrete circular soralium. 46 shape and size of ascospores and conidia but differs in apothecial color due to the brown pigmentation of the exciple and hymenium. Second, the molecular phylogeny published by Reese Naesborg et al. (2007) does not support placing Catillaria croatica in either Catillaria or Lecania. Exclusion from Catillaria is supported by the ascus which is Bacidia type.