The Bryologist 107(4), pp. 459 479 Copyright q 2004 by the American Bryological and Lichenological Society, Inc. The Genus Buellia Sensu Lato in the Greater Sonoran Desert Region: Saxicolous Species with One-septate Ascospores Containing Xanthones FRANK BUNGARTZ Botanische Staatssammlung München, Menzinger Straße 67, D-80638 München, Germany; e-mail: bungartz@ bsm.mwn.de JOHN A. ELIX Department of Chemistry, The Faculties, Australian National University, Canberra, ACT 0200, Australia; e-mail: john.elix@anu.edu.au THOMAS H. NASH III Arizona State University Lichen Herbarium, School of Life Sciences, P.O. Box 87 4601, Tempe, AZ 85287-4601, U.S.A. e-mail: tom.nash@asu.edu Abstract. Six species of saxicolous Buellia s.l. containing xanthones are reported from the Greater Sonoran Desert Region: Buellia concinna, B. halonia, B. mamillana, B. prospersa, B. subaethalea, and B. trachyspora. All species have a pale yellow to greenish yellow thallus characterized by the presence of xanthones. Nevertheless, they all show distinct characters and may consequently only be distantly related. Buellia concinna, a taxon previously reported only from Europe, is the valid name for the North American B. semitensis. Buellia subaethalea, first described by Bouly de Lesdain, but subsequently largely ignored, is reported for the first time from the region. Buellia trachyspora, a subtropical species barely reaching the Sonoran Region, is distinguished from B. mamillana. Keywords. Buellia, lichen taxonomy, lichenized ascomycetes, North America, saxicolous species, Sonoran Desert, xanthones. Lichen species with xanthones can usually easily be recognized by their yellowish thallus color, frequently have a C1 conspicuously orange thallus reaction and usually fluoresce yellow or orange in UV light. Xanthones are lichen metabolites derived from acetyl CoA via the acetyl polymalonyl pathway. Unlike many other lichen substances, they are difficult to distinguish with routine thin-layer chromatography (TLC). High performance liquid chromatography (HPLC) is therefore the preferred method of identification. In Europe, Scheidegger and Ruef (1988) pioneered analyzing xanthones from saxicolous species of Buellia. Xanthones are not common in Buellia and it is currently difficult to evaluate whether species containing xanthones belong to Buellia s.str. All species from the Sonoran Region are well distinguished from one another by distinct morphological, anatomical, and ultrastructural characters. Even though some of these species may be closely related, it is unlikely that all species with xanthones share a common ancestry. Segregating these species from Buellia s.l. does not resolve the taxonomy of the species, and it is currently not advisable to erect new genera that are monotypic or contain only a few species. All spe- cies are therefore included in Buellia s.l. and detailed descriptions are provided including morphological, anatomical, ultrastructural, and chemical characters. MATERIAL AND METHODS All specimens were examined with light microscopy using hand- and cryosections. Both conventional bright field microscopy (BF) and differential interference contrast (DIC) were used. Selected specimens were also studied with transmission electron microscopy (TEM) according to a protocol described in detail by Bungartz et al. (2002). To improve dehydration and infiltration, this protocol has been modified according to Bungartz and Nash (2004b). All specimens were spot tested and routinely examined with standardized thin-layer chromatography (Culberson & Johnson 1982; Culberson & Kristinsson 1970; Orange et al. 2001; White & James 1985). If norstictic acid was present, clusters of orange, needle-shaped crystals were formed in KOH. These are best observed in the compound microscope. TLC-plates were interpreted with the computer program WINTABOLITES (Mietzsch et al. 1994), and scanned for permanent record (Egan 2001). In addition, a subset of specimens were analyzed using standardized high performance liquid chromatography (HPLC, Elix et al. 2003). All specimens examined here fluoresce in UV-light, even though some reactions may be pale (possibly caused by a low concentration of xanthones). 0007-2745/04/$2.25/0 460 THE BRYOLOGIST Thallus medulla, cortex, and transverse sections of the apothecia were tested with Lugols iodine. A highly concentrated or even saturated stock solution (Common 1991) was used if reactions were tested directly on the specimen. When testing the medulla, caution was applied that reactions were not confused with black hyphae from a hypothallus below. If in doubt, thallus transverse sections were carefully re-examined with the compound microscope. To observe sufficient detail within the ascus apex, apothecium transverse sections were tested with a 0.3% IKI solution after a pre-treatment with 5% KOH. Ascus type terminology follows Rambold et al. (1994). The thalli frequently contain crystals of various origins. A simple test with H2SO4 can be indicative for the presence of Ca oxalates (Bungartz & Nash 2004b), but for all specimens examined here this reaction was negative and no clusters of needle-shaped crystals were observed. Terminology referring to spore types is currently in a state of flux and it appears problematic to adopt a single concept. Structurally identical types within Buellia s.l. and Rinodina s.l. have probably evolved independently (Helms 2003), and it may thus be problematic to refer to these types with the same name. Spores measurements are given according to Nordin (2000). Spore ornamentation follows the terminology of Scheidegger (1993). The term ‘‘psilate’’ has not been used. Using a technical term like ‘‘psilate’’ implies that a particular ornamentation should be present. Psilate spores are, however, smooth and thus lack distinct ornamentation. Buellia trachyspora has spores with coarse ornamentation not previously described from Buellia. It is described here as coarsely rugulate or ‘areolate’. Scheidegger (1993) described several distinct exciple types, but his concepts have not generally been adopted because the distinction of the different types relies on cumbersome examination of the excipular plectenchyma. Only thin microtome sections (,15 mm) allow this differentiation to be observed. To clarify Scheidegger’s (1993) concept, line drawings of all types are provided here (Figs. 10–11). Structural variation and differences in pigmentation are mentioned within the descriptions. References to the fungal plectenchyma follow Korf (1973), van Brummelen (1967), and Ryan et al. (2001). Pigment names follow Meyer and Printzen (2000). Their protocol to identify acetone insoluble pigments according to color reactions with HNO3, KOH, and HCl was applied. Most pigments were thus identified. Some color reactions can be misleading because pigments do not occur as pure colors, but are ‘‘superimposed’’ i.e., mixed in different concentrations. In addition, colorless lichen substances like atranorin and norstictic acid react with KOH and further obscure the observations. We are reasonably confident that the most commonly present brown pigment is elachistabrown, even though the reactions are less obvious than described by Meyer and Printzen (2000). The terminology of Vobis (1980) and Vobis and Hawksworth (1981) has been adopted to describe conidiophore types and pycnidium ontogeny. For a detailed discussion of the relevance of conidia and pycnidia as taxonomic characters in Buellia s.l., see Bungartz et al. (2004). Detailed specimen information about all collections at ASU is available at: http//seinet.asu.edu/collections/ selection.jsp. BUELLIA CONCINNA Th. Fr., Nova Acta Reg. Soc. Scient. Upsal. Ser. 3, 3: 332. 1860. TYPE: NORWAY. FINMARK. Varanger, Nesseby, 30 August 1857, Fries s.n. (UPS, lectotype designated by Foucard et al. 2002; BM, GZU, M!, O, PC, isolectotypes). [VOL. 107 Buellia semitensis Tuck., Syn. N. Amer. Lich. 2: 95. 1888. TYPE: U.S.A. CALIFORNIA. Mariposa Co. Granitic rocks, Bolander 329 ex Tuckerman sheet 3281 (FH!, lectotype selected here). Note: The lectotypification is necessary because Tuckerman (1888, p. 96) did not refer to a particular specimen in the protologue: ‘‘Granitic rocks, Yosemite Valley and elsewhere, California, Bolander:’’ For additional synonyms see Scheidegger and Ruef (1988) and Foucard et al. (2002). Thallus (Figs. 1A–B) crustose, thin to moderately thickened, closely aggregated or dispersed, epilithic; granular to minutely bullate; prothallus absent; thallus surface smooth and shiny, rarely matt, usually pale yellow to greenish yellow, rarely becoming pale yellow (older herbarium specimens), epruinose, phenocorticate; medulla lacking Ca-oxalate (H2SO42). Apothecia lecideine; (0.2–)0.3– 0.6(–0.8) mm in diameter; soon sessile; proper margin prominent, usually persistent, rarely excluded with age, black; disc black, epruinose or rarely with faint, yellow pruina, plane, rarely becoming slightly convex with age; exciple distinct, of leptocline-type (Figs. 1C, 10D) i.e., exciple thick, distinct, and not distinctly differentiated into inner and outer part, hyphae thin-walled, prosoplectenchymatous and usually 6 densely interwoven (textura intricata), dull fuscous brown throughout, becoming 6 carbonized by various amounts of brown pigments (cf. elachista-brown), pigmentation continuous with epihymenium, hypothecium deep reddish brown (leptoclinoides-brown, textura intricata); hymenium hyaline, not inspersed; paraphyses simple to moderately branched, apically swollen, with brown (cf. elachista-brown) pigment cap and diffuse, brown pigment (HNO31 violet, cinereorufa-green). Asci 8-spored, clavate, Bacidia-type. Ascospores (Figs. 1D–I) soon becoming pigmented, initially olive, brown at maturity, ellipsoid to 6 crescentshaped i.e., often distinctly curved and characteristically with tapered ends, rarely constricted, (13.0–)15.6–[18.5]–21.3(–24.0) 3 (6.0–)7.9–[8.9]– 9.9(–11.0) mm (n 5 60); one-septate (very rarely with additional median septa forming at both ends), proper septum becomes thickened early during spore ontogeny (Physconia-type; Figs. 1D–E); ornamentation microrugulate, becoming rugulate with age (best seen in DIC); septum with septal pore canal, simple pore, and undifferentiated pore plug; spore wall (Figs. 1G–I) differentiated into cracked, thin perispore (0.11–0.17 mm), narrow intermediate layer (,0.03 mm), thick proper spore wall (0.37– 0.50 mm) and moderately thickened endospore (0.24–0.34 mm). Pycnidia rare, urceolate to globose, unilocular, at maturity almost entirely occupied by densely branched conidiophores; conidiogenous cells mostly terminal, rarely also intercalary (cf. conidiophore-type V); pycnidial ontogeny 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA 461 FIGURE 1. Buellia concinna (A–F. light micrographs; G–I. TEM micrographs). — A. Granular thallus with sessile apothecia (Nash 22836). — B. Close-up of granules with apothecia (Nash 22836). — C. Transverse section of the leptocline-type exciple i.e., largely undifferentiated throughout and composed of intricately interwoven, mesodermatous hyphae (Nash 22836). — D. Mature ascospores with 6 tapered ends and thickened septum (arrow; Nash 22836). — E. Premature, ellipsoid pale ascospore with distinct septum thickening and mature, crescent-shaped ascospore with deeply pigmented wall and moderately thickened septum (Nash 11791). — F. Overmature, 6 citriform ascospore (Nash 22836). — G. Premature ascospore (Nash 14655): (as) ascus wall; (s) mucilaginous sheath; (1) perispore; (2) intermediate layer; (3) proper spore wall; (4) endospore (at this stage of the ontogeny the proper spore wall and the endospore are not yet fully differentiated). — H. Mature ascospore (Nash 14655). — I. Wall layers in a mature ascospore (Nash 14655): (as) ascus wall; (s) mucilaginous sheath; (1) perispore; (2) intermediate layer; (3) proper spore wall; (4) endospore (at this stage of the ontogeny the proper spore wall and the endospore are fully differentiated). 462 THE BRYOLOGIST similar to Umbilicaria-type; conidia simple, bacilliform to ellipsoid, 2.0–4.0 3 1.5–2.0 mm (n 5 20). Chemistry (Fig. 7). Spot test reactions usually C1 orange or sometimes 6 pinkish, K1 yellow, KC1 orange, P1 orange, CK1 orange. UV1 pale or bright yellow to orange. The thallus medulla reacts weakly amyloid or not amyloid. The hymenium is also amyloid. The thallus is characterized by the following xanthones: arthothelin, isoarthothelin, 6-O-methylarthothelin, 4,5-dichloronorlichexanthone, 4,5-dichloro-6-O-methylnorlichexanthone, asemone and thiophanic acid. In addition, gyrophoric, lecanoric and orsellinic acid are often present. Substrate and ecology. On a variety of hard, siliceous (HCl2) rock substrates, often on vertical cliffs. Scheidegger and Ruef (1988) reported that this species often grows as a juvenile parasite on crustose and rarely foliose lichens. The North American specimens are not lichenicolous, but otherwise match the description of B. concinna in Scheidegger and Ruef (1988), Scheidegger (1993), and Foucard et al. (2002). Isolectotype material of B. concinna, examined during a visit to M, as well as a specimen from Scheidegger’s private herbarium are not lichenicolous and agree well with the North American material. Distribution (Fig. 6). Widely distributed throughout the Northern Hemisphere. Within the Sonoran Desert Region only moderately common at higher elevations (montane to subalpine). Notes. Buellia concinna is easily recognized by its distinct granular thallus and the characteristic, crescent-shaped spores. This unusual spore shape is not present in all spores of an apothecium, but can usually be found in at least some of the sections examined from an apothecium. No other species from the Sonoran Region has similar spores. Selected specimens examined.—AUSTRALASIA. NEW ZEALAND. Nash 19094 (ASU).—EUROPE. FRANCE. PYRÉNÉES-ORIENTALES. Scheidegger 7840 (hb. Scheidegger). NORWAY. FINMARK. Fries s.n. (MSC69240).—NORTH AMERICA. MEXICO. HIDALGO. Nash 38098 (ASU). SONORA. Nash 12483 (ASU). U.S.A. ARIZONA. Apache Co. Nash 27088 (ASU), Hertel 40189 (M). Cochise Co. Nash 14596 (ASU); Nordin 5178 (UPS). Coconino Co. Nash 7575 (ASU). Santa Cruz Co. Nash 18578 (ASU). CALIFORNIA. El Dorado Co. Ryan 23591a (ASU). Fresno Co. Thiers 34410 (ASU). Lake Co. Sigal s.n. (ASU). Los Angeles Co. Ryan 26137b (ASU). San Diego Co. Ryan 25821b (ASU). Shasta Co. Nash 22836 (ASU). Tulare Co. Nash 11287 (ASU). Tuolumne Co. Ryan 24231 (ASU). COLORADO. Clear Creek Co. Anderson 6673 (ASU). El Paso Co. Anderson 8293 (ASU). SOUTH DAKOTA. Custer Co. Anderson 7879 (ASU). Unknown Co. Anderson s.n. (MSC63646). BUELLIA 1866. [VOL. 107 HALONIA (Ach.) Tuck., Lich. Californ. 26. Lecidea halonia Ach., Meth. Lich. 47. 1803. TYPE: SOUTH AFRICA. CAPE PROVINCE. Cape of Good Hope. On hard maritime rock [original label data: Caput bonae spei, in saxis durissimis ad littora Africae australioris], Osbeck s.n. (H-Ach–362!, lectotype selected here; several isolectotypes, UPS-ACH, isolectotype); ex herb. Acharius (H-Nyl 9211, possibly a type fragment). Baeomyces capensis Taylor in Hook., London Journ. Bot. 6: 186. 1847. TYPE: SOUTH AFRICA. WESTERN CAPE. Cape of Good Hope. ex hb. Hooker sub. ‘‘9311 Lecidea’’ in Taylor herb. sheet 1460 (FH, lectotype selected here; BM-000660172, BM-000660173, isolectotypes). Lecidea disciformis var. halonia (Ach.) Nyl., Mém. Soc. Imp. Sci. Natur. Cherbourg 5: 126. 1857. Buellia disciformis var. halonia (Ach.) Boist., Nouv. Flore Lich. 2: 235. 1903. Diploicia capensis (Taylor) Dodge, Beih. Nov. Hedwigia 38: 157. 1971. Possible synonyms: Buellia flavoareolata (Nyl.) Müll. Arg., Hedwigia 31: 283. 1892. Lecidea flaveoareolata Nyl., Annal. Scienc. Nat. Bot., ser. 4, 3: 166. 1855. TYPE: CHILE. QUEBRADA. Quilmenco, 318459 S, 718059 W. (H-Nyl, syntype). Note: Specimens from Chile (Coquimbo Province) distributed by Weber Lich. Exs. 564a, b (ASU, SBBG), and material collected by Imshaug on an Expedition to Santa Clara (Juan Fernandez Islands, Chile; MSC-0005485, MSC-0005486, MSC-0005487, MSC-0005488) are morphologically and anatomically similar, if not identical to B. halonia. These specimens were analyzed with TLC by R. C. Harris, who detected atranorin and an unknown xanthone. Imshaug annotated several other specimens (see specimens examined) from San Juan Fernandez (Chile) as B. halonia. These specimens were not examined by TLC or HPLC, but agree well with B. halonia. The type of B. flavoareolata has not been studied, but it is very likely that it is a synonym of B. halonia. Thallus (Figs. 2A–B) crustose, thick, 6 continuous, epilithic; areolate; prothallus distinct, delimiting thallus as black outline; thallus surface smooth and matt to 6 shiny, usually yellowish green to pale yellow, rarely becoming pale yellow (older herbarium specimens), epruinose, phenocorticate; medulla lacking Ca-oxalate (H2SO42). Apothecia lecideine; (0.2–)0.3–0.5(–0.7) mm in diameter; initially immersed, young apothecia frequently 6 aspicillioid, soon bursting through thallus surface and becoming adnate to sessile; proper margin prominent, usually persistent, rarely excluded with age, black, frequently with coarse thallus fragments attached; disc black, epruinose, sometimes with yellowish pruina, plane, rarely becoming strongly convex with age; exciple distinct, of leptocline-type (Figs. 2C–D, 10D) i.e., exciple thick, distinct, and not distinctly differentiated into inner and outer parts, hyphae thin-walled, prosoplectenchymatous, and usually 6 densely interwoven (textura intricata), dull fuscous brown to aeruginose throughout, becoming 6 car- 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA 463 FIGURE 2. Buellia halonia (Nash 41434; A–F. light micrographs; G–L. TEM micrographs). — A. Areolate thallus with immersed sessile apothecia. — B. Close-up of areoles and apothecia: immature apothecia are immersed and large chunks of thalline material (arrows) often remain attached during emergence. — C. Transverse section of the leptoclinetype exciple. — D. Detail of outer exciple: mesodermatous hyphae are not considerably swollen at apices and 6 interwoven throughout exciple. — E. Ascus with eight mature ascospores (arrow indicates septum thickening). — F. Mature ascospore with distinct septum thickening (arrow). — G. Immature ascospore. — H. Wall layers in an immature ascospore: (as) ascus wall; (1) outer layer (perispore and mucilaginous sheath not distinctly differentiated); (2) inner layer (proper wall and endospore not distinctly differentiated). — I. Mature ascospore: septum thickening of endospore is not yet developed. — J. Pycnidium. — K. Conidiophores with bacilliform conidia. — L. Wall layers in mature ascospore: (as) ascus wall; (s) mucilaginous sheath; (1) perispore; (2) intermediate layer; (3) proper spore wall; (4) endospore. 464 THE BRYOLOGIST bonized by various amounts of brown and aeruginose pigments (cf. elachista-brown & cinereorufagreen), pigmentation continuous with epihymenium, but aeruginose pigment not extending into deep reddish brown hypothecium (leptoclinoidesbrown, textura intricata); hymenium hyaline, not inspersed; paraphyses simple to moderately branched, apically swollen, with brown pigment cap (cf. elachista-brown) and diffuse, aeruginose pigment (HNO31 violet, cinereorufa-green). Asci 8-spored, clavate, Bacidia-type. Ascospores (Figs. 2E–I, L) soon becoming pigmented, initially olive, brown at maturity, oblong to ellipsoid, usually not constricted, with obtuse ends, not curved, (11.5–) 12.4–[14.1]–15.7(–19.0) 3 (6.0–)6.8–[7.4]–8.0(– 9.0) mm (n 5 60); one-septate, proper septum soon but only briefly thickened during ontogeny (Physconia-type; Figs. 2E–F); ornamentation weakly microrugulate (in DIC); septum with septal pore canal, simple pore, and undifferentiated pore plug; spore wall (Figs. 2H, L) differentiated into smooth, thin perispore (0.14–0.20 mm), narrow intermediate layer (, 0.05 mm), thick proper spore wall (0.35– 0.44 mm), and moderately thickened endospore (0.18–0.34 mm). Pycnidia (Fig. 2J) rare, urceolate to globose, unilocular, at maturity almost entirely occupied by densely branched conidiophores; conidiogeneous cells mostly terminal, rarely also intercalary (cf. conidiophore-type V, Fig. 2K); pycnidial ontogeny similar to Umbilicaria-type; conidia simple, bacilliform, 5.0–7.0 3 1.0–1.5 mm (n 5 20). Chemistry (Fig. 7). Thalli typically react K1 yellow, P1 orange, C1 orange, KC1 orange, and CK1 orange. The thallus fluorescence is typically UV1 bright yellow to orange. The thallus is not amyloid, but the hymenium reacts amyloid. The following xanthones were detected with HPLC: arthothelin, isoarthothelin, 2,4-dichloronorlichexanthone, 2,5-dichloronorlichexanthone, 2,7-dichloronorlichexanthone, 4,5-dichloronorlichexanthone, 5,7-dichloronorlichexanthone, thiophanic, and thiophaninic acid. Two bis-xanthones, eumitrin X and eumitrin Y, have been detected with HPLC in part of the specimens. Their chemical structure is currently unresolved. Atranorin is regularly present, frequently accompanied by norstictic acid. Substrate and ecology. Growing abundantly on maritime siliceous mineral-poor coastal rock (generally HCl2). Distribution (Fig. 6). Currently known from the Pacific coast of North America, South Africa, Australia, and Chile (see notes on B. flaveoareolata, which is possibly a synonym of B. halonia). Reports of B. halonia from Europe belong to B. concinna according to Scheidegger and Ruef (1988). In the Sonoran Region, very common along [VOL. 107 the coast of southern California and Baja California. Notes. Buellia halonia has frequently been confused with Lecidella asema (Nyl.) Knoph & Hertel, a crustose lichen with similar color, often growing in the same habitat. In the field, granulose thalli of L. asema can usually be distinguished from areolate thalli of B. halonia. This distinctly different morphology is often sufficient for identification, but the two species are more reliably distinguished by microscopic examination: Lecidella asema has simple, hyaline spores. Spores of Buellia halonia are brown and one-septate. Selected specimens examined.—AUSTRALASIA. AUSTRALIA. SOUTH AUSTRALIA. Streimann 54946 (MSC354293).—AFRICA. SOUTH AFRICA. CAPE PROVINCE. Eaton s.n. (BM, H-Nyl 2210); unknown collector (H-Nyl 9212).—NORTH AMERICA. MEXICO. BAJA CALIFORNIA. Nash 4910, 8719, 25186, Ryan 21332 (ASU); Kalb 24668a (hb. Kalb); Weber L-36628 (COLO); Wetmore 63671 (MIN). BAJA CALIFORNIA SUR. Nash 40017 (ASU). U.S.A. CALIFORNIA. Lake Co. Toren s.n. (SFSU), Hasse s.n. (ASU). Los Angeles Co. Marsh 6500, Nash 32020, Ryan 30942 (ASU); Weber L-42957 (COLO). San Diego Co. Bratt 5628 (SBBG). San Luis Obispo Co. Nash 36976, Riefner 88-431 (ASU). San Mateo Co. Shushan S14688 (ASU). Santa Barbara Co. Nash 32573, 33102, Ryan 31184, Weber Lich. Exs. 680 (ASU); Weber L-80190 (COLO). Ventura Co. Nash 37035 (ASU); Weber S1734 (COLO).—SOUTH AMERICA. CHILE. JUAN FERNANDEZ. Imshaug 37584 (MSC-113121), 38241 (MSC-113136), 38236 (MSC-113137). BUELLIA MAMILLANA (Tuck.) W. A. Weber, Mycotaxon 27: 493. 1986. Rinodina mamillana Tuck., Proc. Amer. Acad. 7: 226. 1866 (1868). TYPE: U.S.A. HAWAII. Honolulu. Oahu. Volcanic Rocks, Mann s.n. ex sheet no. 2124a (FH, holotype; W!, isotype). Lecidea glaziouana Kremp., Flora 59: 317. 1876. TYPE: BRAZIL. RIO DE JANEIRO. On granitic rocks [original label data: ad saxa granitica], Glaziou 3506 (M0023763!, lectotype selected here; M-0023765!, BM000660175!, C!, G! W!, isolectotypes). Lecidea recepta Kremp., Flora 59: 318. 1876. TYPE: BRAZIL. RIO DE JANEIRO. On granitic rock. [original label data: ad saxa granitica], 1869, Glaziou 3295 (M0023811!, lectotype selected here; M-0023810!, isolectotype). Buellia glaziouana (Kremp.) Müll. Arg., Flora 63: 19. 1880. Buellia recepta (Kremp.) Müll. Arg., Linnaea 43: 36. 1880. Rinodina thomae Tuck., Syn. N. Americ. Lich. 1: 209. 1882. TYPE: U.S.A. ALABAMA. Lawrence Co. Sandstone Rocks at Moulton, 348289 N 878179 W, ca. 190 m, Peters s.n. (5 ex Tuckerman sheet no. 2125) (FH, holotype; MICH, isotype). Rinodina contiguella Vain., Étude Lich. Brésil 1: 164. 1890. TYPE: BRAZIL. RIO DE JANEIRO. On granitic rock [original label data: ad saxa granitica], Glaziou 3506 (M!, lectotype selected here). Lecidea cohibilis Nyl., Sertum ich. Trop. Labuan et Singapore 41. 1891. TYPE: U.S.A. TENNESSEE. At Lookout 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA Tower mountain, on sandstone, Calkins s.n. (H-Nyl, holotype; F, FH, MICH, MO, NY, US, isotypes). Buellia contiguella (Vain.) Malme, Bih. K. Svenska Vet.Akad. Handl. 28: 5. 1902. Buellia moreliiensis de Lesd., Lich. Mex. 26. 1914. TYPE: MEXICO. MICHOACÁN. Morelia. On volcanic rocks (US!, lectotype selected here). Note: The material from US is selected here as the lectotype because the holotype material was probably destroyed in World War II. Imshaug (1955) reported that he had seen type material from Magnusson’s private herbarium. Buellia poliocheila Vain., Ann. Acad, Sci. Fenn. ser. A 6(7): 85. 1915. TYPE: U.S.A. VIRGIN ISLANDS. St. Thomas. On rocks at Ma Folie, Biese s.n. (C, holotype; TUR, isotype). Melanaspicilia contiguella (Vain.) Vain., Ann. Acad. Sci. Fenn. ser. A 6: 79. 1915. Buellia sensitiva Zahlbr., Mycologia 22: 78. 1930. TYPE: U.S.A. PUERTO RICO. Naranjito. In an open field, 25 November 1915, Fink 102 (MICH!, holotype). Buellia cohibilis (Nyl.) Zahlbr., Cat. lich. univ. 7: 344. 1931. Buellia antillarum de Lesd., Bull. Museum Hist. Nat. Paris II 15: 470. 1934. TYPE: FRENCH WEST INDIES. GUADELOUPE ISLAND. Cove south of Bouillante. On volcanic rock at sea level. [original label data: Anse du Sud de Bouillante] collector not known (PC, holotype). Buellia thomae (Tuck.) Imshaug comb. ined., in Imshaug University Microfilms no. 2607. 1951. Buellia glaziouana var. poliocheila (Vain.) Imshaug, Farlowia 4: 493. 1955. Buellia glaziouana var. sensitiva (Zahlbr.) Imshaug, Farlowia 4: 494. 1955. Possible synonym: Buellia subglaziouana S.R. Singh & D.D. Awasthi, Biological Memoirs 6: 190. 1981. TYPE: INDIA. MADHYA PRADESH. Hoshangabad district, Pachmarhi, on way to Chhota Mahadeo, altitude ca 1,050 m, 26 January 1973, Singh 73.157 (AWAS, holotype). Note: No type material of B. subglaziouana has been studied. Singh and Awasthi (1981) described B. subglaziouana as different from B. glaziouana because of a deep iodine-blue medulla reaction. However, contrary to the protologue, B. glaziouana also has a distinctly I1 blue medulla. Buellia subglaziouana could therefore be considered a synonym of B. mamillana (5 B. glaziouana). Thallus (Figs. 3A–B) crustose, thin to moderately thick, 6 continuous, epilithic; rimose, rarely becoming rimose-areolate; prothallus distinct, delimiting thallus as black outline; thallus surface smooth and matt, rarely 6 shiny, usually pale greenish yellow, rarely gray (older herbarium specimens), epruinose, phenocorticate; medulla lacking Ca-oxalate (H2SO42). Apothecia of mamillana-type (Figs. 3C–D, 11A–B) i.e., initially lecanorine, but soon becoming lecideine; (0.3–)0.6–0.9(–1.1) mm in diameter; usually adnate to sessile, rarely remaining immersed; proper margin thickening with maturity, inconspicuous in immature apothecia, but soon becoming distinct, brownish black; disc dark brown to blackened, epruinose, plane, usually 6 convex with age; exciple of immature apothecia thin, indistinct but soon thickening i.e., inner ex- 465 cipular hyphae distinct, hyaline but becoming pigmented with age, prosoplectenchymatous (textura angularis), distinct, not reduced, similar in structure and orientation to deep reddish brown hypothecium (leptoclinoides-brown, textura intricata), outer excipular hyphae short-celled, cells angular, 6 swollen (textura angularis), and usually 6 carbonized with various amounts of brown pigments (cf. elachista-brown), pigmentation continuous with epihymenium; hymenium hyaline, not inspersed; paraphyses simple to moderately branched, apically swollen, with brown (cf. elachista-brown) pigment cap. Asci 8-spored, clavate, Bacidia-type. Ascospores (Figs. 3E–G) soon becoming pigmented, initially olive, brown at maturity, oblong to ellipsoid, usually not constricted, with obtuse ends, not curved, (10.5–)12.0–[13.8]–15.7(–18.5) 3 (5.5–)6.3–[7.0]– 7.8(–10.0) mm (n 5 60); one-septate, proper septum soon but only briefly thickened during spore ontogeny (6 Physconia-type); ornamentation rugulate; septum with septal pore canal, simple pore, and undifferentiated pore plug; spore wall (Fig. 3G) differentiated into smooth to cracked, thick perispore (0.32–0.43 mm), indistinct intermediate layer (,0.01 mm), thin proper spore wall (0.09–0.16 mm) and moderately thickened endospore (0.17–0.28 mm). Pycnidia rare, urceolate to globose, unilocular, at maturity almost entirely occupied by densely branched conidiophores; conidiogeneous cells mostly terminal, rarely also intercalary (cf. conidiophore-type V); pycnidial ontogeny similar to Umbilicaria-type; conidia simple, fusiform, 6.0–14.0 3 1.0–1.5 mm (n 5 20). Chemistry (Fig. 8). Thalli usually react K1 yellow, P2 or P1 yellow, C2, KC2, CK2, but these spot tests are sometimes weak. Thalli generally fluoresce UV1 bright or pale yellow to orange. Both thallus medulla and apothecia react distinctly amyloid, even though Vainio (1915) and Malme (1902) reported a negative iodine reaction. Imshaug (1955) first noticed this reaction and Weber (1986) confirmed his observation. The following xanthones where detected with HPLC: 4,5-dichloro-3O-methylnorlichexanthone, 4,5-dichlorolichexanthone, 4-chlorolichexanthone. Atranorin is typically also present, frequently accompanied by haematommic acid and methyl b-orsellinate (both artifacts formed by hydrolysis of atranorin). 29-O-methylperlatolic, divaricatic, norstictic, hypostictic, stictic, methylstictic, cryptostictic acid, and one unknown trace substance have occasionally also been detected by HPLC. Substrate and ecology. On shaded, steep, 6 vertical, siliceous rock faces (HCl2). Distribution (Fig. 6). Known from tropical to subtropical localities throughout the world (Mexi- 466 THE BRYOLOGIST [VOL. 107 FIGURE 3. Buellia mamillana (A–E. light micrographs, F–G. TEM micrographs). — A. Rimose thallus with immersed to 6 sessile apothecia (Nash 28439). — B. Close-up thallus and apothecia (Nash 25875; arrows indicate thalline part of margin in some premature apothecia). — C. Transverse section of immature apothecium (Nash 25604) with distinct thalline outer exciple [ca 60 mm wide; (c) cortex; (a) algae], and a narrow (ca 10 mm wide) inner exciple (arrows). — D. Transverse section of premature apothecium (Nash 25604): proper exciple (arrows) is expanding (ca 30 mm wide) while the outer, thalline exciple (th) becomes excluded (ca 35 mm wide). — E. Mature ascospores with rugulate ornamentation (Nash 25604). — F. Mature ascospore (Nash 37836). — G. Wall layers in mature ascospore (Nash 37836): (as) ascus wall; (s) mucilaginous sheath; (1) perispore; (2) intermediate layer; (3) proper spore wall; (4) endospore. 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA co: Bouly de Lesdain 1914, Caribbean: Imshaug 1955, 1957, Brazil: Malme 1902, India: Singh & Awasthi 1981, southeastern USA: Tuckerman 1888). In the Sonoran Region, a montane subtropical species, especially common in the Sierra Madre Occidental and Southern Baja California. Notes. Based on the development of the apothecia, Imshaug (1955) distinguished three lines of development in B. mamillana and recognized two of these lines as varieties: 1) with apothecia remaining immersed, 2) with apothecial initials frequently abortive (var. poliocheila), and 3) with a depsidone and a K1 red spot test reaction, forming crystals (var. sensitiva). This range of variation can be explained if apothecial anatomy is examined carefully. All apothecia are initially immersed, but eventually emerge from the thallus with a distinct thalline margin. Immature apothecia do not appear abortive because spores are frequently formed even in young apothecia that are not yet enclosed by a distinctly colored envelope. The considerable variation in thallus chemistry, as confirmed by HPLC, would suggest that Imshaug’s varieties might correlate with distinct chemotypes and if so, these varieties would deserve separate taxonomic recognition. Material examined here could, however, not be segregated into distinct chemotypes. It was not possible to correlate the chemical variation with any of the ‘‘developmental lines’’ described by Imshaug (1955), therefore no distinct varieties are recognized here. Selected specimens examined.—CENTRAL AMERICA. BRITISH ANTILLES. ST. LUCIA. Imshaug 30160, 30160 (MSC-347926, MSC-347926). COSTA RICA. Pittier s.n. (BM-000660174, BM-000671861). CUBA. LA HABANA. Imshaug 24815 (MSC-75987). DOMINICAN REPUBLIC. DE LA VEGA. Imshaug 23738 (MSC-76115); Wetmore 23738 (MSC-76115). ECUADOR. GALAPAGOS ISLANDS. Weber Lich. Exs. 110 (M-0061342); Hill s.n., ex sheet no. 2124a (FH). FRENCH ANTILLES. GUADELOUPE. LeGallo 2707 (MSC-60972). SAINT-BARTHÉLEMY. LeGallo 2665 (MSC-61050), 2655 (MSC-61038). JAMAICA. ST. ANDREW PARISH. Imshaug 14454, 13808 (MSC-76027, MSC-76062). SAINT VINCENT & THE GRENADINES. SAINT VINCENT . Imshaug 30568, 30568 ( MSC-347923, MSC347923).—NORTH AMERICA. MEXICO. BAJA CALIFORNIA. Ryan 21461 (ASU). BAJA CALIFORNIA SUR. Nash 29793, 33778, 16953 (ASU). CHIHUAHUA. Nash 31295 (ASU). NAYARIT. Nash 39192 (ASU). SINALOA. Nash 10086, 12214 (ASU). SONORA. Marsh 5918, Nash 25518, 25524, Ryan 21625, 21636 (ASU); Wetmore 69963 (COLO). U.S.A. ARIZONA. Cochise Co. Nash 9653b, Ryan 10704 (ASU). Gila Co. Nash 28439. Pima Co. Nash 7984 (ASU). Santa Cruz Co. Nash 25875 (ASU). ARKANSAS. Garland Co. Wetmore 86251 (MSC-379125). HAWAIIAN ISLANDS. Kauai. Nash 20829 (ASU); Hawaii. Bailey 353 (DUKE). LOUISIANA. Natchitoches Co. Tucker 17523 (M-0061343). TENNESSEE. Hamilton Co. Calkins 224, 236 (MSC-146694, MSC120013). TEXAS. Nacogdoches Co. Wetmore 17638 (MIN).—SOUTH AMERICA. ARGENTINA. TUCUMAN. Lamb 5164 (MSC-117950). BRAZIL. RIO DE JANEIRO. Vai- 467 nio Lich. Bras. Exs. 74 (M-0061345, BM-000671862); Glaziou s.n. (MSC-122653); Lamb 5014 (MSC-338305). SÃO PAULO. Kalb Lich. Neotrop. Exs. 46 (M-0061341); Lamb 5013 (MSC-117955). CHILE. ISLA DE PASCUA (5 EASTER ISLAND). Skottsberg s.n. (BM-000671861). PARAGUAY. DEPARTMENTO DE PARAGUARI. Malme 1486B (MSC129597). BUELLIA PROSPERSA (Nyl.) Riddle, Brookl. Bot. Gardens Memoirs 1: 114. 1918. Recent synonyms.—Rinodina lecideina Mayrhofer & Poelt, Bibl. Lich. 12: 112. 1979. Amandinea lecideina (H. Mayrhofer & Poelt) Scheid. & H. Mayrhofer, in Scheidegger, Lichenologist 25: 342. 1993. For a detailed description see Bungartz et al. (2004). BUELLIA SUBAETHALEA de Lesd., Lichens du Mexique 27. 1914. TYPE: MEXICO. MICHOACÁN. Morelia, Santa Maria mountain ridge [original label data: Loma Santa Maria] 2,000 m, Frère Arsène Brouard 3654 (MSC 48484!, lectotype selected here; US!, S!, isolectotypes). Note: The lectotype is selected here because the original material in Dunkerque was probably destroyed in World War II. Thallus (Figs. 4A–B) crustose, thin to moderately thickened, 6 continuous, epilithic; granular-areolate to verrucose; prothallus absent or delimiting thallus as black outline; thallus surface smooth and matt to 6 shiny, usually pale yellow, rarely becoming yellowish gray (in the herbarium), epruinose, phenocorticate; medulla lacking Ca-oxalate (H2SO42). Apothecia lecideine; (0.1–)0.2–0.4(–0.6) mm in diameter; immersed, becoming adnate to sessile; proper margin thin, reduced, inconspicuous, black; disc black, epruinose, plane, rarely becoming slightly convex with age; exciple narrow, poorly differentiated, of aethalea-type (Figs. 4C, 10B) i.e., inner excipular hyphae narrow, hyaline, prosoplectenchymatous (textura oblita), often reduced, similar in structure and orientation to paraphyses, transient with deep reddish brown hypothecium (leptoclinoides-brown, textura intricata), outer excipular hyphae parallel, moderately swollen (textura oblita) and usually strongly carbonized with various amounts of brown pigments (cf. elachistabrown, HNO32), pigmentation continuous with epihymenium; hymenium hyaline, not inspersed; paraphyses simple to moderately branched, apically swollen, with brown (cf. elachista-brown) pigment cap. Asci 8-spored, clavate, Bacidia-type. Ascospores (Figs. 4D–I) soon becoming pigmented, initially olive, brown at maturity, oblong to ellipsoid, often constricted, with obtuse ends, not curved, (12.0–)14.2–[16.4]–18.6(–22.0) 3 (6.0–)7.1–[8.1]– 9.0(–11.0) mm (n 5 60); one-septate, proper septum developing soon and rarely thickened during spore ontogeny, with two dark bands across each cell 468 THE BRYOLOGIST [VOL. 107 FIGURE 4. Buellia subaethalea [A–D. light micrographs (Arsène 3654 — lectotype), E–I. TEM micrographs (Ryan 27029)]. — A. verrucose-areolate thallus. — B. Close-up of verrucose-areolate thallus with 6 immersed to sessile apothecia. — C. Transverse section of mature apothecium with aethalea-type exciple. — D. Mature, rugulate ascospore with two distinctly darkened bands (arrows). — E. Ascus with immature ascospores. — F. Immature ascospore: (as) ascus wall; (1) outer layer (perispore and mucilaginous sheath not distinctly differentiated); (2) inner layer (proper wall and endospore not distinctly differentiated). — G. Wall in immature ascospore. — H. Wall layers in mature ascospore: (s) mucilaginous sheath; (1) perispore; (2) intermediate layer; (3) proper spore wall; (4) endospore. — I. Mature ascospore. Note: the two bands that are distinctly visible in the light microscope (Fig. 4A), do not correspond with any distinct wall structure in the TEM (Figs 4F–I). 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA (Fig. 4D; similar to Physconia- and/or Bicinctatype); ornamentation rugulate; septum with septal pore canal, simple pore, and undifferentiated pore plug; spore wall (Figs. 4G–J) differentiated into fractured, thick perispore (0.31–0.47 mm), narrow intermediate layer (,0.04 mm), moderately thickened proper spore wall (0.17–0.29 mm) and moderately thickened endospore (0.12–0.22 mm). Pycnidia rare, urceolate to globose, unilocular, at maturity almost entirely occupied by densely branched conidiophores; conidiogeneous cells mostly terminal, rarely also intercalary (cf. conidiophore-type V); pycnidial ontogeny similar to Umbilicaria-type; conidia simple, bacilliform, 7.0–11.5 3 1.0–1.5 mm (n 5 20). Chemistry (Fig. 8). The thallus reacts K1 yellow to orange (forming crystals), P1 yellow to orange, C2, KC2, and CK2. Thalli show a dull fluorescence i.e., UV1 deep orange. The thallus is not amyloid, but the hymenium reacts amyloid. The only xanthone found in this species is 4,5-dichlorolichexanthone. In addition, norstictic, cryptostictic, methylstictic, and stictic acid were detected. Substrate and ecology. On a variety of siliceous (HCl2) rock substrates. Distribution (Fig. 6). A montane, subtropical species, infrequent in southeastern Arizona and probably more common towards the Sierra Madre Occidental. Originally described from Michoacán, Mexico but little is presently known about the extent of the distribution. Notes. Buellia subaethalea is superficially similar to B. concinna, but the thallus is verrucoseareolate rather than granular and the oblong to ellipsoid spores are usually distinctly ‘‘banded’’ and never crescent-shaped (see Discussion–Asci and Ascospores). Selected specimens examined.—NORTH AMERICA. MEXICO. CHIHUAHUA. Nash 31382 (ASU). DURANGO. Nash 31087 (ASU). SINALOA. Nash 10147 (ASU). SONORA. Nash 10871 (ASU). U.S.A. ARIZONA. Apache Co. Nash 26815 (ASU). Cochise Co. Ryan 10748 (ASU); Weber L-36928 (COLO). Gila Co. Nash 39439 (ASU). Pima Co. Darrow 722, Nash 21208 (ASU). Santa Cruz Co. Nash 25353 (ASU). TEXAS. Brewster Co. Nash 15037b (ASU). BUELLIA TRACHYSPORA Vain., Annal. Acad. Sc. Fennic. ser. A 6(7): 84. 1915. TYPE: U.S.A. VIRGIN ISLANDS. St. John Co. Reef Bay, on a cliff along a cataract [original label data: Indias occ. S. Jan, Reef Bay, In rupe ad cataractam], 7 March 1906, Boergesen 19067-3 (5 Vainio 09521a) (C!, lectotype; TUR-10017!, isolectotype, both selected by Imshaug 1955). Note: The former Danish Virgin Island ‘‘St. Jan’’ is now part of the U.S.A. and more frequently referred to by its English name ‘‘St. John’’. Imshaug (1955) regarded material in C as the holotype because most of Vainio’s tropical material is deposited there. However, the protologue 469 does not mention a particular herbarium (C or TUR). Imshaug’s annotation thus must be interpreted as a lectotypification (see Art. 10.5 ICBN). The material in TUR is thus isolectotype material. Only a small fragment of this isolectotype material (Boergesen 9521a) was made available for study at ASU. This fragment is annotated as ‘‘only part of the type (# 9521) S. Huhtinen, Curator, Turku University Herbarium (TUR)’’. The lectotype material at C is a well developed, large specimen and annotated in Vainio’s handwriting as ‘‘type’’. Buellia gyrosa Vain., Annal. Acad. Sc. Fennic. ser A. 6(7): 85. 1915. TYPE: U.S.A. VIRGIN ISLANDS. St. John Co. On rock. 15 March 1906, Boergesen s.n. (Vainio 9583; C!, lectotype; TUR, isolectotype, both selected by Imshaug 1955). Note: Imshaug (1955) studied type material from C and TUR and argued that B. gyrosa ‘‘. . . differs from B. trachyspora only in the gyrose nature of the apothecia. . . ’’ (p. 505). The older apothecia of the type specimen have a folded margin. We agree with Imshaug’s (1955) assessment that this variation ‘‘. . . scarcely warrants species recognition’’ (p. 505). Again Imshaug’s (1955) annotation is in effect a lectotypification. Thallus (Figs. 5A–B) crustose, thin, 6 continuous, epilithic; rimose to rimose-areolate; prothallus distinct, delimiting thallus as black outline; thallus surface smooth and matt, not shiny, usually pale greenish yellow, rarely gray (herbarium specimens), epruinose, phenocorticate; medulla lacking Ca-oxalate (H2SO42). Apothecia lecideine; (0.3–) 0.4–0.9(–1.8) mm in diameter; soon sessile; proper margin black, conspicuously thickened and frequently fractured, always persistent, not excluded with age; disc black, epruinose, plane, not becoming convex with age; exciple very thick, distinctly differentiated into inner and outer parts, of trachyspora-type (Figs. 5C–D, 11C) i.e., inner excipular hyphae large, leptodermatous, 6 isodiametric cells, reddish brown, paraplectenchymatous (textura angularis), transient with deep reddish brown hypothecium (leptoclinoides-brown, textura intricata), outer excipular hyphae short-celled, cells globose, mesodermatous (textura globularis) and extremely carbonized with large amounts of brown pigments (cf. elachista-brown), pigmentation continuous with epihymenium; hymenium hyaline, not inspersed; paraphyses simple to moderately branched, apically swollen, with brown pigment cap (cf. elachista-brown). Asci 8-spored, clavate, Bacidiatype. Ascospores (Figs. 5E–G) soon becoming pigmented, initially olive, brown at maturity, oblong to ellipsoid, sometimes constricted, with obtuse ends, not curved, (14.0–)18.8–[22.6]–26.5(–34.0) 3 (8.0–)8.7–[9.6]–10.5(–12.0) mm (n 5 60); oneseptate (occasionally additional septa forming at both ends of spore cells), proper septum and spore wall narrow, not thickening during spore ontogeny [Beltraminea (5 Buellia)-type]; ornamentation coarsely rugulate to areolate; septum with septal 470 THE BRYOLOGIST [VOL. 107 FIGURE 5. Buellia trachyspora (Nash 20750; A–E. light micrographs, F–G. TEM micrographs). — A. Rimose thallus. — B. Close-up of apothecia. — C. Transverse section of mature apothecium with trachyspora-type exciple: (1) outer, strongly carbonized exciple; (2) inner, paraplectenchymatous exciple; (3) hypothecium extending into inner exciple. — D. Detail of outer and inner exciple: (1) strongly carbonized cells of outer exciple cannot be distinguished from one another; (2) leptodermatous, 6 isodiametric cells of inner exciple. — E. Mature ascospores with strongly rugulate to areolate ornamentation. — F. Mature Ascospore. — G. — Wall layers in mature ascospore: (s) mucilaginous sheath; (1) perispore; (2) intermediate layer; (3) proper spore wall; (4) endospore. 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA pore canal, simple pore, and undifferentiated pore plug; spore wall (Fig. 4G) differentiated into coarsely fractured, thick perispore (0.27–0.97 mm), narrow intermediate layer (,0.05 mm), thick proper spore wall (0.38–0.53 mm) and thick endospore (0.27–0.43 mm). Pycnidia rare to common, urceolate to globose, unilocular, at maturity almost entirely occupied by densely branched conidiophores; conidiogenous cells mostly terminal, rarely also intercalary (cf. conidiophore-type V); pycnidial ontogeny similar to Umbilicaria-type; conidia simple, bacilliform to fusiform, 10.0–13.0 3 0.5–1.0 mm (n 5 20). Chemistry (Fig. 9). All spot tests are negative (K2, P2, C2, KC2, CK2), but the thallus has a UV1 bright orange fluorescence. The thallus medulla is not amyloid and apothecia react amyloid. Only xanthones detected with HPLC: 4,5-dichloro3-O-methylnorlichexanthone, 4,5-dichlorolichexanthone. No other substances were found. Substrate and ecology. On sheltered siliceous rock (HCl2), usually close to rivers and streams. Distribution (Fig. 6). The species was first described from the Virgin Islands and included by Imshaug (1957) in his Catalogue of the West Indian Lichens (Cuba, Jamaica, Puerto Rico, Virgin Islands: St. Thomas, St. John). This subtropical to tropical species barely reaches the southernmost Greater Sonoran Desert Region in southwestern Chihuahua (Barranca del Cobre, La Bufa, COLOWeber L-65270). Additional collections at ASU were collected near Compostella in Nayarit, Mexico (outside the Greater Sonoran Desert Region). Notes. Although this species has a unique apothecial anatomy, it has been confused with B. mamillana. Thalli of the two species are indeed similar, but young apothecia of B. trachyspora emerge early during the ontogeny and are never remotely lecanorine (not even a thalline collar or a thalline veil has been observed in the material). Selected specimens examined.—MEXICO. NAYARIT. Nash 20751 (ASU). CHIHUAHUA. Weber L-65270 (COLO). KEY TO THE SPECIES 1. Inner exciple distinctly paraplectenchymatous, with large, leptodermatous isodiametric cells; outer exciple very strongly carbonized (small globular cells barely distinguished even in thin microtome sections); spores with coarsely rugulate to areolate ornamentation (clearly visible at 4003) --------------------------------------------------------- Buellia trachyspora 1. Inner and outer exciple not as above; spores smooth to rugulate but not coarsely areolate (ornamentation, if present, barely visible at 4003) ----------------------------------------------------------------------------------------- 2 2. Thallus granular to bullate or verrucose-are- 3. 3. 5. 5. 471 olate i.e., entirely composed of small granules or areoles with distinctly granular surface ------ 3 2. Thallus rimose to areolate, not verrucose or granular ------------------------------------------------------------------ 4 Mature spores oblong to ellipsoid, with obtuse ends, not curved, with two spore cells covered by broad, darkened band; thallus granular-areolate to verrucose --------------------------------------- Buellia subaethalea Mature spores ellipsoid to 6 citriform, often with 6 tapered ends, frequently curved (crescentshaped), the two spore cells never covered by darkened band; thallus granular to minutely bullate ------------------------------------------------------ Buellia concinna 4. Apothecial disc deep brown, rarely blackened; young apothecia remaining immersed, or if emergent, distinctly lecanorine i.e., with distinct thalline margin; thalline margin darkening and eventually excluded; apothecia becoming lecideine with age; ascospores rugulate --------------------------------------------- Buellia mamillana 4. Apothecial disc black, not brownish black; young apothecia sometimes emerging with thalline veil but never distinctly lecanorine; ascospores smooth to inconspicuously microrugulate ------------------------------------------------------------------ 5 Thallus thick, areolate; usually with distinct black prothallus along thallus margin; apothecia pruinose or epruinose; exciple thick, of intricately intertwined hyphae, carbonized by diffuse, aeruginose (HNO31 violet) pigment; conidia bacilliform to fusiform -------------------------------------------- Buellia halonia Thallus thin, rimose to rimose-areolate; with or without faint black prothallus; apothecia epruinose; exciple thin, of narrow, parallel hyphae with swollen end cells, carbonized by brown, non-aeruginose pigment (HNO32); conidia filiform ------------------------------------------------------------------ Buellia prospersa DISCUSSION Thallus. Even though all species can be characterized by xanthones, thallus color varies considerably among the species. Some species like B. prospersa and B. mamillana may have very pale thalli and the presence of xanthones in these thalli may thus be overlooked. Thalli of B. subaethalea and B. concinna become sordid yellow with prolonged herbarium storage. Buellia halonia is usually greenish yellow rather than pale yellow. The presence of xanthones in the thalli is generally indicated by a yellow to orange fluorescence in longwave (ca 350 nm) ultraviolet light. Intensity of this fluorescence; however, varies from pale to very bright even among thalli of the same species. Buellia concinna and B. halonia both have a C1 and KC1 orange thallus, but the other species usually have no indicative C (or KC) reaction even though their thalli contain xanthones. Thallus morphology for each of the species is quite distinct and most species can usually be recognized even without anatomical analysis. Buellia prospersa has thin, usually inconspicuous, rimose thalli (Bungartz et al. 2004). In comparison, thalli of B. halonia are much thicker and distinctly are- 472 THE BRYOLOGIST [VOL. 107 FIGURE 6. Distribution of species treated here in the Greater Sonoran Desert Region (Floristic Provinces according to Shreve & Wiggins 1964). olate (Figs. 2A–B). The thallus of Buellia concinna is composed of small and 6 dispersed granules (Figs. 1A–B), whereas B. subaethalea has a verrucose surface of an essentially areolate thallus (Figs. 4A–B). Buellia mamillana and B. trachyspora have very similar smooth, rimose thalli which are finely fissured (Fig. 3A–B, 5A–B). These two species are difficult to distinguish by their thalline characters alone and have thus been confused. Apothecia. Buellia trachyspora and B. mamillana have apothecia that are unique among species in the genus Buellia. Apothecia of B. trachyspora become very large (up to 1.8 mm in diameter). Unlike in B. mamillana these large apothecia very 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA FIGURE 7. 473 HPLC chromatograms of Buellia concinna (Nash 38098) and Buellia halonia (Nash 17166). soon emerge and become sessile. They remain distinctly flattened, with a plane disc and a thick margin (Fig. 5B). Due to the extreme carbonization of the outer exciple, this margin often becomes coarsely fractured in dry herbarium specimens. The carbonized cells of the outer exciple are small and 6 globose, and can barely be distinguished because of their strong carbonization. The inner exciple is entirely composed of large, isodiametric cells and thus distinctly paraplectenchymatous (Figs. 5C–D, 474 THE BRYOLOGIST FIGURE 8. [VOL. 107 HPLC chromatograms of Buellia mamillana (Nash 29793) and Buellia subaethalea (Nash 25353). 11C). Because of the angular shape of these cells the plectenchyma may be referred to as textura angularis. The inner exciple of B. trachyspora is entirely composed of thin-walled cells that are not carbonized. In contrast, many other Buellia species have an outer exciple of 6 angular cells, which are smaller, carbonized, and mesodermatous. This texture has also been referred to as textura angularis but is quite different from the texture seen in B. trachyspora (Bungartz & Nash 2004b,c; Bungartz 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA FIGURE 9. 475 HPLC chromatogram of Buellia trachyspora (Weber L-65279). et al. 2004; Scheidegger 1993). The exciple of B. trachyspora is therefore unique and cannot be assigned to any of the types described by Scheidegger (1993). Buellia mamillana is the only species currently known from the Sonoran Region with apothecia developing a distinct thalline margin (Figs. 3B–D). Other species currently included in Buellia s.l. may have some irregular thalline collar (Bungartz & Nash 2004b) or a thalline veil (Bungartz & Nash 2004a), but only in Buellia mamillana do the young apothecia develop a distinct lecanorine margin with a cortex and algal layer embracing the young apothecium (Figs. 3C, 11A). As a result, the species was originally described as a Rinodina. It is unusual that this initially well developed thalline margin subsequently becomes excluded and replaced by hyphae from the proper exciple (Figs. 3D, 11B). During this process the deep brown pigmentation of the disc extends more and more across the initially pale margin. This shift in pigmentation is a result of internal growth processes. The inner exciple expands and the thalline outer part becomes excluded. During this ontogeny, apothecia may even have a lecanorine exciple on one side, and a lecideine exciple on the other side of a transverse section. This ontogeny is unusual, and Weber (1986) who transferred the species into Buellia, did not describe this unusual ontogeny. He interpreted the apothecia as ‘‘clearly lecideine’’, possibly because older apothecia indeed become lecideine. Apothecia of the other species are not as unusual. Scheidegger (1993) already described the intricately interwoven excipular hyphae of B. halonia (Figs. 2C–D) and assigned it to the leptocline-type. This exciple type is not significantly differentiated throughout and it is initially less strongly pigmented inside but soon becomes evenly pigmented. Buellia concinna has an exciple similar to B. halonia, but lacks the aeruginose pigment. Like in B. halonia, excipular hyphae of B. concinna are 6 evenly pigmented, little differentiated, and intricately interwoven (Figs. 1C, 10D). Despite this, Scheidegger (1993) assigned the exciple of B. concinna to the dispersa-type (Fig. 10C), which he described as composed of hyphae radiating from a deep reddish brown hypothecium, with a 6 hyaline transition zone and a strongly carbonized outer layer of moderately swollen cells. The exciple of B. concinna does not show this differentiation and thus should be assigned to the leptocline-, not the dispersa-type. The exciple of B. subaethalea is less prominent and the inner hyphae are thinner than in B. halonia or B. concinna. In B. subaethalea only the outer cells are usually 6 swollen and strongly pigmented (Fig. 4C). The exciple of B. prospersa is similar (Bungartz et al. 2004). Both species belong struc- 476 THE BRYOLOGIST [VOL. 107 FIGURE 10. Line drawings of exciple types in Buellia s.l. — A–B. Variation of the aethalea-type exciple, characterized by thin, more or less parallel hyphae, similar in orientation and structure to paraphyses. — A. Apothecia remaining immersed and exciplular hyphae strongly reduced (e.g., Buellia aethalea and Buellia eganii, see Bungartz & Nash 2004a). — B. Apothecia emerging and excipular hyphae becoming pronounced (e.g., Buellia subaethalea, or B. spuria and B. stellulata, see Bungartz & Nash 2004a). — C. The dispersa-type: inner, mesodermatous hyphae radiate from hypothecium towards outer exciple. Pigmentation in young apothecia does not extend far into central exciple, but with age exciple becomes evenly pigmented. Outermost cells are distinctly swollen, shorter, and more isodiametric (e.g., Buellia dispersa and B. nashii, see Bungartz 2004, Bungartz et al. 2002). — D. The leptocline-type: hyphae are mesodermatous, little differentiated throughout, and with age more and more intricately interwoven (e.g., Buellia concinna and B. halonia). turally to the aethalea-type (Fig. 10B), even though they lack the aeruginose pigment cinereorufagreen. Asci and Ascospores. All species have Bacidiatype asci and a dark hypothecium, characters typically associated with the Buellia-clade rather than the Rinodina-clade (Helms et al. 2003). Ascospores of all species are not pigmented at very early stages, soon become olive, and are distinctly brown at maturity. Buellia trachyspora has spores with no distinct septum thickening and may thus be assigned to the Buellia (5 Beltraminea)-type, even 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA 477 FIGURE 11. Line drawings of exciple types in Buellia s.l. (continued). A.–B. The mamillana-type (currently known only from Buellia mamillana). — A. At early stage of ontogeny a distinct thalline exciple is still present. — B. Thalline exciple becomes excluded by a progressively expanding proper exciple. — C. The trachyspora-type: differentiated into strongly carbonized outer exciple of small, globular cells and reddish brown, large-celled and distinctly paraplectenchymatous inner exciple (currently known only from B. trachyspora). — D. The vilis-type: hyaline hypothecium of thin, strongly interwoven hyphae extends into inner exciple and reacts very strongly iodine-blue; outermost exciple is deeply pigmented with blackish red pigment atra-red (currently known only from Buellia vilis, see Scheidegger 1993 and Bungartz 2004). though the spores are usually 6 constricted along the septum and younger spores show some inconspicuous swelling where the septum forms. The ascospores of all other species have a distinct septum thickening at least during some part of their ontogeny. They can thus be referred to the Physconiatype. In most species this septum thickening is ephemeral i.e., it is most pronounced in premature spores but becomes reduced in mature and overmature spores. Only B. prospersa has a septum, which usually is more persistent and considerably thicker than in any of the other species. These spores could, therefore, also be referred to as Orcularia-type. None of these spore types refers to strictly distinctive categories, but represent an idealized concept of an inherently dynamic and transient development of the spore. For example, even though both B. concinna and B. subaethalea may formally be assigned to the same spore type, their spore ontogenies are distinctly different from all of the other species. Spores of B. concinna develop a distinctive shape (Figs. 1D–F). The premature to mature ascospores are characteristically curved and have 6 tapered or pointed ends. These spores are 478 THE BRYOLOGIST best described as a ‘‘half-moon’’ or crescent-shaped (Fig. 1E). The characteristic shape is not always observed because some spores do not become curved. These spores nevertheless develop 6 tapered ends and thus appear 6 citriform. All other species have spores with obtuse ends. Old spores of B. subaethalea frequently become 6 constricted, but are more importantly characterized by two, broad, and distinctly darkened bands across each of the two spore cells (Fig. 4D). In the light microscope these bands feign lateral wall thickenings that must not be confused with distinct structural lateral thickenings in Callispora-type ascospores. Ultrastructural observations currently suggest that the ‘‘banding’’ does not correspond with structural layers of the lateral cell walls. However, comparing the ultrastructure of ascospores at different ontogenetical stages may elucidate whether these patterns correspond to some ultrastructural differentiation of the spore wall. Similar ‘‘bands’’ are known from ascospores of Rinodina (for example, the Bicincta-type) and may be caused by a phenomenon similar to the torus. Spore ornamentation is a result of the perispore differentiation. Thus, the ultrastructure of this outer spore wall layer corresponds to the ornamentation observed in the microscope. In B. trachyspora, the perispore appears coarsely fractured in the TEM (Figs. 5F–G) and a rugulate to areolate ornamentation (Fig. 5E) is visible in light microscope even at 4003 magnification. In other species, spore ornamentation can also be observed, but is much less distinct. Buellia subaethalea also has rugulate ascospores (Figs. 4D, I), but the ornamentation is barely visible at 4003 and distinct only at 1,0003 magnification. The rugulate ornamentation of Buellia mamillana is even less distinct (Fig. 3E) and the perispore is not strongly fractured (Fig. 3G). Finally, B. halonia and B. prospersa both have a microrugulate ornamentation. This fine ornamentation is quite distinct at 1,0003 in B. prospersa, but barely visible in B. halonia. Conidiomata. The conidiomata of all species are quite similar. They develop in urceolate to globose pycnidia (Fig. 2J) that are almost entirely occupied by conidiophores. These conidiophores are branched and predominantly form conidia at the apices (Fig. 2K). Some conidia are also formed intercalary on short bayonet-like protrusions. The conidiophores do, however, not anastomose at their apices and thus resemble more closely type V instead of type VI (Vobis 1980). Buellia concinna has the shortest, 6 ellipsoid conidia. Buellia halonia and B. subaethalea have slightly longer, bacilliform conidia. Conidia of B. mamillana and B. trachyspora are bacilliform to fusiform and B. prospersa has filiform conidia. Because of its long conidia, B. [VOL. 107 prospersa also has been accommodated in the genus Amandinea [as Amandinea lecideina (H. Mayrhofer & Poelt) Scheid. & H. Mayrhofer]. The segregation of an entire genus on this single character is, however, problematic (Bungartz et al. 2004). Chemistry (Figs. 7–9). Detailed information on the thallus chemistry of the species is provided in the species descriptions. Buellia concinna and B. halonia are the only species that contain asemone, thiophanic acid, and arthothelin together with the closely related isoarthothelin. The other species contain a variety of different lichexanthones that are also present in B. concinna and B. halonia. Buellia subaethalea is the only species that contains a single xanthone (4,5-dichchlorolichexanthone). In contrast, B. mamillana has the most complex chemistry, regularly with a variety of xanthones, depsides, and depsidones. This chemical variation does not appear to correlate with any morphological difference. Distribution (Fig. 6). Of all the species examined only B. halonia shows a distinctly coastal, maritime distribution. Buellia concinna and B. subaethalea are montane to subalpine species and possibly occur in the same habitats. Buellia mamillana and B. trachyspora show subtropical affinities. Buellia mamillana extends far into the Sonoran Desert Region and typically grows along mountain streams. Buellia trachyspora grows in similar habitats but barely extends into the southernmost part of the Sonoran Region. ACKNOWLEDGMENTS We are grateful to John Sheard, University of Saskatchewan, Canada and Scott Bates and James Lendemer ASU, Arizona, for reviewing the original manuscript. Roland Moberg, Museum of Evolution, Uppsala and an anonymous reviewer provided additional instructive advice. Hannes Hertel and Dagmar Triebel, Botanische Staatssammlung München, helped resolve questions regarding the correct typification of several taxa. Ulrik Søchting and Eric Hansen, University of Copenhagen (Denmark) and Seppo Huhtinen, University of Turku (Finland) provided valuable advice on the correct typification of Buellia trachyspora. Several lichenologists responded quickly to a literature search for rare taxonomic literature posted on the lichen list server. Loans from the following herbaria to ASU are greatly appreciated: BM, C, CANL, COLO, FH, H, hb. Scheidegger, hb. Kalb, hb. Sheard, L, M, MICH, MSC, SBBG, TUR, UPS, and W. This study was supported by a Research Grant in Plant Systematics from the International Association of Plant Taxonomists (IAPT) and National Science Foundation Awards to ASU (DEB-0103738, DEB9701111). A research visit of the first author to MSC was supported by a National Science Foundation Award (DBI0237401). LITERATURE CITED BOULY DE LESDAIN, M. 1914. Lichens du Mexique (états de Puebla et du Michoacan) recueillis par le frère Arsène Brouard. imp. I. Escalante, S.A. 2004] BUNGARTZ ET AL.: SAXICOLOUS BUELLIA BUNGARTZ, F. 2004. New and previously unrecorded saxicolous species of Buellia s.l. with one-septate ascospores from the Greater Sonoran Desert Region. Mycotaxon 90: 81–123. ——— & T. H. NASH III. 2004a. 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