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Institute of Botany, Academia Sinica, Nankang, Taipei 115, Taiwan
Jack D. Rogers
Department of Plant Pathology, Washington State University, Pullman, Washington 99164-6430
Huei-Mei Hsieh
Institute of Botany, Academia Sinica, Nankang, Taipei 115, Taiwan
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSTAXONOMYDISCUSSIONLITERATURE CITED |
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The diagnosis of Theissenia is emended to include taxa that lack a definite central perithecial columella and taxa that feature ascospores with a germ slit. Theissenia cinerea is described as a new species that lacks a perithecial columella; T. eurima is described as a new species with ascospores having a germ slit. The type species, T. pyrenocrata, is redescribed and compared with the new species. The taxonomic position of Theissenia is discussed.
Key words: Nodulisporium, systematics, Xylariaceae
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYDISCUSSIONLITERATURE CITED |
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). Maublanc (1914) recognized that the morphology of the perithecia was not typical of the genus of the basionym, Ustulina pyrenocrata Theiss. In particular, he recognized an invagination of the stroma beneath each perithecium, resulting in a conspicuous central bulge or umbo in the perithecium from which the hymenium arises. Maublanc (1914) called this central bulge a columella and presented a sketch of a section through a perithecium. In his diagnosis of Theissenia he wrote, "—hymenium gelatinosum, columellam e fundo perithecii assurgentem tegens." In his description of T. pyrenocrata he wrote, "—columella ovoidea, elongata vel depressa, extus fertili, intus nucleo nigro zona cellulosa pallescente tecto praedita." Maublanc (1914) described the asci as "soon dissolving." He discussed the numerous paraphyses that agglutinated with ascospores and ascus remains into a gelatinous mass. Dennis (1964) confirmed and expanded Maublanc's observations based upon material from Africa under the epithet "pycnocratera." He noted that the columella in African material is "less constant and regular in form" than Maublanc's description. Dennis (1964) also remarked that the diffluent asci lack an apical apparatus and that ascospores lack a germ slit. He was unsure of its taxonomic position. Læssøe (1994) and Eriksson (1999) accepted Theissenia as a member of the Xylariaceae. Herein we describe two new species of Theissenia. Each deviates from the type species in a significant way. One species lacks a definite perithecial columella and the other has ascospores with a definite germ slit. Including them in Theissenia necessitates an emendation of the genus.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYDISCUSSIONLITERATURE CITED |
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). Hyphal tips emerging from the stromatal contents then were cut and transferred to fresh media. Therefore, the isolates obtained presumably originated from multiple ascospores. These isolates were cultured on 2% Difco oatmeal agar (OMA, 60 g oatmeal, 12.5 g Difco Bacto agar, 1000 mL water), 2% SMEA, and/or 2% Difco potato dextrose agar with 5 g/L yeast extract (PDYA, 200 g potato infusion, 20 g Difco Bacto dextrose, 15 g Difco Bacto agar, 5 g Difco yeast extract, 1000 mL water) and incubated in 9-cm diam Petri dishes at 25 C under 12 h continuous fluorescent light. Material mounted in water was observed by bright field (BF) and differential interference contrast (DIC) microscopy. Material for scanning electron microscopy (SEM) was subjected to critical point drying and coating with gold, and was then examined with a Zeiss DSM950 instrument. The color designations are from Rayner (1970). Cultures were deposited in the Culture Collection and Research Center (CCRC) in Taiwan. |
TAXONOMY |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYDISCUSSIONLITERATURE CITED |
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Type species. T. pyrenocrata (Theiss.) Maubl.
Stromata effused-pulvinate with thin dehiscent outer layer; persistent layer carbonaceous extending downward to encase each perithecium in a discrete carbonaceous chamber. Material between and beneath perithecial chambers fibrous and soft. Central part of perithecia with a more or less conspicuous bulge or columella or lacking a definite columella. Asci clavate, long-stipitate, lacking an apical ring, soon deliquescing. Ascospores brownish, one-celled, without definite germination site or with germ slit. Perispore indehiscent or dehiscent in 10% potassium hydroxide (KOH).
Key to the Theissenia Species Treated
1. Ascospores with a germ slit . . . . . T. eurima
1. Ascospores lacking a germ slit . . . . . 2
2. Ascospores with striations on the dorsal side only . . . . . T. pyrenocrata
2. Ascospores lacking striations . . . . . T. cinerea
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Stromata late effuse-pulvinata, marginibus devexis, 0.7–7 cm longa x 0.4–3 cm lata x 1.5–2 mm crassa, strato externo dehiscenti albo papyraceo praedita. Superficies stromatis matura glauca vel murina, plana; textura proxime sub superficie carbonacea deorsum extensa omne perithecium cingens; textura inter loculis peritheciorum fibrosa mollis; textura sub peritheciis tenuis fibrosa mollis praedita. Perithecia globosa, 0.7–1.2 mm diam, sine columella. Ostiola umbilicata. Asci cum ascosporis octo irregulariter dispositis, clavati, evanidi; asci immature metientes 50–75 µm longitudine tota x 15–24 µm crassi, partibus sporiferis 30–40 µm longitudine, sine annulo apicali. Ascosporae dilutae brunneae vel brunneae, unicellulares, cylindricae vel ellipsoideae leviter inequilaterales apicibus latis, leves, 17–21 x 6–7 µm, sine rima germinativa. Perisporium in KOH dehiscens; episporium leve. Paraphyses abundans ca 4 µm crassae.
Stromata widely effused-pulvinate, with beveled margins, 0.7–7 cm long x 0.4–3 cm broad x 1.5–2 mm thick, with white paper-like dehiscing layer; mature surface Lavender Grey (125) to Pale Mouse Grey (117), plane; carbonaceous immediately beneath surface and extending downward to encase each perithecium; tissue between encased perithecia fibrous and soft; tissue beneath perithecia thin and fibrous. Perithecia globose, 0.7–1.2 mm diam, lacking definite columella. Ostioles lower than stromatal surface, with openings umbilicate. Asci with 8 ascospores arranged irregularly, evanescent, measurable only when immature, clavate, 50–75 µm total length x 15–24 µm broad, the spore-bearing parts 30–40 µm long, lacking an apical ring. Ascospores pale brown to light brown, unicellular, cylindrical or ellipsoid, slightly inequilateral, with broadly rounded ends, 17–21 x 6–7 µm, lacking a germ slit; perispore dehiscent in 10% KOH; epispore smooth. Paraphyses copious, septate, 4 µm broad, extending beyond ascal tips.
Culture and anamorph. Colonies on OMA reaching the edge of Petri dish in 1 wk, whitish, velvety, azonate, with submerged margins, becoming Sulphur Yellow (15) to Greenish Yellow (16), eventually blackish, overlain with a thin layer of Isabelline (65) hyphae. Reverse Cinnamon (62). Sporulation scanty.
Colonies on SMEA reaching the edge of Petri dish in 1 wk, whitish, velvety, azonate, with submerged margins, becoming Honey (64) on surface and blackish underneath, with abundant dark brown, bramble-like structures produced on vegetative hyphae. Reverse Dull Green (70). Sporulating regions scattered over entire surface of colony, Honey (64). Conidiogenous structure with Nodulisporium-like branching pattern as defined in Ju and Rogers (1996). Conidiophores hyaline or yellowish, roughened, di- or trichotomously branched, sometimes with additional branches arising from the first level of conidiogenous regions, 3–3.5 µm diam, with 2–3 conidiogenous cells arising from each terminus. Conidiogenous cells cylindrical, hyaline, smooth or finely roughened, 15–22 x 2–2.5 µm, bearing one to several denticulate conidial secession scars on apical region. Conidia produced holoblastically in sympodial sequence, hyaline, smooth, cylindrical to clavate, 8–12 x 1.5–2 µm, with flattened base indicating former point of attachment to conidiogenous cell.
Specimens examined. TAIWAN. TAIWAN PROV.: Ping-tung Co., Heng-chun, Ken-ting, on wood stump, 16 Jul 2001, Hsieh, H.-M. & Ju, Y.-M. 90071615 (CULTURED) (HOLOTYPE HAST, ISOTYPE WSP); Heng-chun, Ken-ting, on wood stump, 16 Sep 2000, Hsieh, H.-M. & Ju, Y.-M. 89091602 (CULTURED) (HAST).
Commentary.
Theissenia cinerea features a smooth, grey stromatal surface, a whitish outer dehiscing stromatal layer, globose perithecia that lack a definite columella, pale ascospores that lack striations, a dehiscent ascospore perispore, and a homogenous outer stromatal crust. Although a definite columella is lacking in the perithecia, scars on the underlying stroma indicate a central attachment of the perithecium to the stroma and probably represents a columellar fundament (Fig. 6). It is interesting to note that, among the xylariaceous genera that form bipartite stromata, T. cinerea is the only species with a dehiscent ascospore perispore, a feature commonly found in Daldinia and Hypoxylon, two genera with unipartite stromata. The abundant, dark brown bramble-like structures produced on vegetative hyphae (Fig. 18) are noteworthy as they are uncommon in Xylariaceae. The anamorph of T. cinerea was scarce on OMA but was abundant on SMEA. The conidia are cylindrical or clavate, produced in sympodial sequence at the apex of a conidiogenous cell, with the youngest conidium formed below the previous one. The anamorph is referable to the form-genus Nodulisporium Preuss. Among the xylariaceous genera with bipartite stromata, Jumillera J. D. Rogers et al and Whalleya J. D. Rogers et al are also known to produce elongated conidia (Rogers et al 1997). These two genera differ from Theissenia primarily in having persistent asci with a distinct apical ring and in lacking a carbonaceous stromatal layer discretely enclosing individual perithecia, and in never showing a perithecial columella. Despite having much smaller perithecia and ascospores, Whalleya appears to have an anamorph bearing some resemblance to that of T. cinerea (Rogers et al 1997). Jumillera, on the other hand, has a coelomycetous anamorph with conidia produced in slimy masses; in some species, a Geniculosporium synanamorph is also produced (Rogers et al 1997).
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Stromata late effuse-pulvinata marginibus devexis, fragmentaria, 6 cm longa x 3 cm lata x 3–4 mm crassa. Superficies stromatis matura vinacea grisea, plana; textura proxime sub superficie carbonacea deorsum extensa omne perithecium cingens; textura inter loculis peritheciorum fibrosa mollis in interstitiis texturae carbonaceae superantis extensa; textura sub peritheciis tenuis fibrosa mollis praedita. Perithecia plus minusve globosa, 2–3(–4) mm diam, cum columella media conspicua hymenium ferens. Ostiola umbilicata. Asci diffluentes, non visi. Ascosporae brunneae, unicellulares, ellipsoideae vel ellipsoideo-inequilaterales parietibus incrassates, leves, 23–29.5 x 9–12 µm, rima germinativa recta plus minusve longitudine sporae. Paraphyses diffluentes.
Stromata widely effused-pulvinate, with beveled margins, fragmentary, 6 cm long x 3 cm broad x 3–4 mm thick; mature surface Vinaceous Grey (116), plane; carbonaceous immediately beneath surface and extending downward to encase each perithecium; tissue between encased perithecia fibrous and soft, extending into interstices of overlying carbonaceous stroma; tissue beneath perithecia thin and fibrous. Perithecia more or less globose, 2–3(–4) mm diam, with conspicuous central columella bearing the hymenium. Ostioles lower than stromatal surface, with openings umbilicate. Asci deliquescing, not observed. Ascospores brown, unicellular, ellipsoid to ellipsoid-inequilateral with thick wall, smooth, 23–29.5 x 9–12 µm, with straight germ slit more or less spore-length. Paraphyses not observed.
Culture and anamorph. Colonies on OMA reaching edge of Petri dish in 2 wk, Mouse Grey (118) with Umber (9) concentric zones near periphery, eventually becoming blackish and overlain with lighter concentric zones overall, lanose. Reverse Luteus (12) to nearly black. Mycelium forming bramble-like aggregations throughout.
Colonies on PDYA reaching edge of 9 cm Petri dish in 4–5 wk, whitish, thin, appressed, producing greyish areas at edge of dish where sporulation was most abundant. Conidiophores brownish, sparingly branched from bramble-like aggregations with conidiogenous region terminal, producing solitary conidia in apparently holothallic manner. Conidia Fuscous (103), subglobose to irregular, at first smooth, becoming somewhat warty, bearing a conspicuous broad secession scar, 11–14 x 11–14 µm.
Specimen examined. BRAZIL. AMAZONAS: Pico Rondon, Perimetral Norte Km 211, igapo forest vic FUNAI, on wood, 23 Mar 1984, Pipoly, J. & Rodrigues, W., Samuels, G. J. 1114 (CULTURED) (HOLOTYPE INPA, ISOTYPE NY, ISOTYPE WSP).
Commentary. Theissenia eurima resembles the type species in having a strongly columellate perithecium. It differs primarily in having ascospores with a germ slit, in ascospore dimensions, and in having smooth stromata that lack lacunae, although fibrous tissue extends into carbonaceous tissue as in the type species. It differs from T. cinerea in having ascospores with a germ slit, in ascospore dimensions, in lacking a dehiscent ascospore perispore, and in having a definite columella.
Colonies of T. eurima resemble those of T. cinerea in producing abundant bramble-like hyphal aggregations. Colonies of T. eurima died soon after covering the culture dish. Transfers were thus made while colonies were actively growing, but none have survived. The anamorph is probably to be regarded as aleuriosporic, i.e., as terminal chlamydospores. Chlamydospores are rarely seen among xylariaceous fungi, having been reported in Nemania aenea (Nitschke) Pouzar (as Hypoxylon) (Petrini and Rogers 1986) and Hypoxylon haematostroma Mont. (as H. crocopeplum) (Rogers et al 1987).
Ustulina pyrenocrata Theiss., Ann. Mycol. 6: 347. 1908.
Numulariola pyrenocrata (Theiss.) P. Martin, J. S. African Bot. 35: 291 (1969) [nom. inval. (Art. 37.1)]; J. S. African Bot. 42: 78 (1976, validation).
Stromata widely effused-pulvinate, with beveled margins, fragmentary, up to 10 cm long x 5 cm broad x 4–6 mm thick; outer dehiscing layer dark brown on surface and black inside, 0.2 mm thick; mature surface Fuscous Black (104), slightly roughened, becoming pitted with age; external tissue 1–1.5 mm thick, carbonaceous immediately beneath surface and extending downward to encase each perithecium; tissue between encased perithecia fibrous and soft, extending into interstices of overlying carbonaceous stroma; tissue beneath perithecia inconspicuous to consipicuous, woody, greyish brown. Perithecia globose, 2–4.5 mm diam, with central umbo or columella conspicuous or inconspicuous. Ostioles lower than stromatal surface, with openings umbilicate. Asci evanescent, measurable only for those before ascospore formation, clavate, up to 95 µm total length x 11–13 µm broad, lacking apical ring. Ascospores light brown to brown, unicellular, cylindrical or ellipsoid, slightly inequilateral, with broadly rounded ends, 14–22(–24) x 6–7.5 µm, lacking germ slit; perispore indehiscent in 10% KOH; epispore with several less than spore-length striations on the dorsal side and smooth on the ventral side. Paraphyses not found.
Specimens examined. BRAZIL. São Leopoldo, Parecy Novo, on wood, no date, Rick, J. (BPI 625273); no locality, on wood, no date, Rick, J. (GZU-Petrak's coll. no. 2108); Pará, Amazon River, on wood, 25 Aug 1923, Weir, J. R. (BPI 625288). SRI LANKA. Peradeniya, on decaying trunk of Artocarpus integrifolia, Nov 1913, Petch, T. 4924, as Nummularia porosa (ISOTYPE BPI 716355, ISOTYPE GZU-Petrak's coll. no. 2136, ISOTYPE K(M) 90689). ZAIRE. CENTRAL FOREST DIST.: Yangambi, on wood of Celtis brieyi, no date, Fassi, B. 579, as Theissenia pycnocratera [sic.] by Dennis, R.W.G. (BR); Yangambi, on wood of Oxystigma oxyphyllum, no date, Fassi, B. 1000, as Theissenia pycnocratera [sic.] by Dennis, R.W.G. (BR); Yangambi, on wood of Oxystigma oxyphyllum, no date, Fassi, B. 1100, as Theissenia pycnocratera [sic.] by Dennis, R.W.G. (BR).
Commentary.
Ascospores of T. pyrenocrata are cylindrical to ellipsoid, having a width range 6–7.5 µm but tending to show increased widths in over-mature specimens, with some ascospores up to 10 µm broad. The striations on the dorsal side of the ascospores observed by light micrography (Fig. 26) appear to be slightly ridged by SEM (Fig. 27); they are much less than spore-length. Maublanc (1914) described the asci as "longe pedicellatis clavatis, mox diffluentibus, 8-sp., circ. 120–125 x 12–16 (non maturis)" and paraphyses as "copiosis, longissimis filiformibus, tenuissime septatis, 3–4 µ crassis." Among the specimens that we had studied, asci were found only in Fassi 579 from BR. The only measurable ones had not yet formed ascospores; this may account for the smaller ascus size range that we obtained compared to those reported by Maublanc (1914). We did not observe paraphyses. The outer stromatal crust is composed of carbonaceous tissue and brown, woody tissue. The carbonaceous tissue forms a honeycomb-like network with the interstices filled with the brown, woody tissue that disintegrates over time and exposes irregular lacunae (Figs. 22, 23). The pitted surface of aged stromata apparently led Petch (1924) to name his Sri Lanka collection Nummularia porosa. Miller (1961) considered N. porosa to be a synonym of T. pyrenocrata, whereas Dennis (1964) was inclined to treat them as separate species because of the smaller ascospores in type material of the former. We have studied the isotypes of N. porosa from BPI, GZU, and K. They are in poor condition; only a small number of ascospores were found. Although the ascospores have largely collapsed, it is still possible to see striations on some of them. Our ascospore measurements are 14–18 x 7–8.5 µm. We thus consider N. porosa a synonym of T. pyrenocrata. It should be noted that Petch (1924) cited specimen no. 3934 as the type of N. porosa in the protologue but labeled the isotypes at BPI and K as no. 4924. Dennis (1964) introduced orthographic variant "pycnocratera" for this fungus and those specimens at BR and K that he had studied were all thus labeled.
This fungus is widely distributed in the tropics. Collections have been made from Africa, Asia, and South America.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYDISCUSSIONLITERATURE CITED |
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erected Theissenia are not present in the two new taxa proposed herein. Theissenia cinerea lacks the definite columella, although stromatal scars indicate a central attachment of the perithecia to the stroma. Moreover, Dennis (1964) remarked that the columella was not universally well-developed among various collections of the type species, an observation corroborated during our examination of those collections. Theissenia eurima ascospores have a germ slit, a feature lacking in the other two taxa. However, Hypoxylon, Xylaria, and Biscogniauxia, among undoubted xylariaceous genera, have taxa with ascospores that apparently lack the germ slit. Examples include Hypoxylon rectangulosporum Y.-M. Ju et al, Xylaria magnoliae J. D. Rogers, and Biscogniauxia arima San Martín et al. The Nodulisporium anamorph of T. cinerea is typical of the Xylariaceae, although that of T. eurima is not. G. J. Samuels (pers comm) observed an anamorph similar to that reported here for T. eurima in cultures from probably what is T. pyrenocrata from Sierra Leone. We presently consider Theissenia to be a member of the Xylariaceae. It is possible, and perhaps likely, that Theissenia will be shown to occupy an isolated position among ascomycetes. It has been suggested to us that Theissenia could be allied with the Diatrypaceae. This is an interesting possibility that, among others, should be assessed on future molecular and other data.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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Accepted for publication May 24, 2002.
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LITERATURE CITED |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSTAXONOMYDISCUSSIONLITERATURE CITED |
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Eriksson OE., 1999 Outline of Ascomycota. Myconet 3:1-88
Ju Y-M, Rogers JD., 1996 A revision of the genus Hypoxylon. Mycologia Memoir no. 20. St. Paul: APS Press. 365 p
Kenerley CM, Rogers JD., 1976 On Hypoxylon serpens in culture. Mycologia 68:688-691
Læssøe T., 1994 Index ascomycetum 1. Xylariaceae. Syst Ascomycetum 13:43-112
Maublanc A., 1914 L'Ustulina pyrenocrata Theissen, type du genre nouveau Theissenia. Bull Soc Mycol France 30:48-53
Miller JH., 1961 A monograph of the world species of Hypoxylon. Athens: Univ. Georgia Press. 158 p
Petch T., 1924 Xylariaceae Zeylanicae. Ann Roy Bot Gard (Peradeniya) 8:119-166
Petrini LE, Rogers JD., 1986 A summary of the Hypoxylon serpens complex. Mycotaxon 26:401-436
Rayner RW., 1970 A mycological colour chart. Kew: Commonwealth Mycological Institute. 34 p. + charts I & II
Rogers JD, Callan BE, Samuels GJ., 1987 The Xylariaceae of the rain forests of North Sulawesi (Indonesia). Mycotaxon 29:113-172
Rogers JD, Ju Y-M, San Martín F., 1997 Jumillera and Whalleya, new genera segregated from Biscogniauxia. Mycotaxon 64:39-50
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