Allosoma Syd., Annls

Thambugala, Kasun M., Singtripop, Chonticha, Chunfang, Yu, Mckenzie, Eric H. C., Liu, Zuo-Yi, Chukeatirote, Ekachai & Hyde, Kevin D., 2014, Towards a natural classification of Dothideomycetes 7: The genera Allosoma, Austropleospora, Dangeardiella, Griggsia and Karschia (Dothideomycetes incertae sedis), Phytotaxa 181 (1), pp. 34-46 : 35-38

Allosoma Syd., Annls mycol. 24(5/6): 353 (1926)

MycoBank: MB 143

Parasitic or saprobic on leaves and wood in terrestrial habitats. Sexual state: Ascomata superficial, sub-circular, uni or multi-loculate, appressed hyphal peridium , branched, septate, dark brown to black, with papillae-like outgrowth in the central region. Hamathecium lacking pseudoparaphyses. Asci 8-spored, bitunicate, globose-subglobose, thickwalled, apedicellate, without a well-developed ocular chamber. Ascospores multi-seriate, broadly ellipsoid, ends rounded, brown to dark brown, 1-septate, constricted at the septum, smooth-walled. Asexual state: hyphomycetous, “ Acrodesmis ”. Conidiophores formed on sexual ascoma, erect, straight or flexuous, elongate, dark brown, some branched at the apex, septate, thick-walled, smooth-walled. Conidiogenous cells polyblastic, integrated, terminal, sympodial, oblong, brown to dark brown and rough. Conidia ellipsoid to oblong, rounded at the apex, slightly tapered at the base, aseptate, hyaline and smooth-walled.

Type species:— Allosoma cestri Syd., Annls mycol. 24(5/6): 353 (1926) MycoBank: MB 260358. FIG. 1 a–q .

≡ Acrodesmis cestri Syd., Annls mycol. 24(5/6): 424 (1926), Index Fungorum number: IF 260357

≡ Periconiella cestri (Syd.) M.B. Ellis, Mycol. Pap. 111: 29 (1967), Index Fungorum number: IF 335847

Epiphytic on leaves. Superficial hyphae irregularly branched, anastomosing, septate. Sexual state: Ascomata 123–166 µm diam, superficial, sub-circular, subglobose, appressed hyphal peridium composed of few layers of polygonal cells, branched, septate, brown to dark brown. Hamathecium lacking pseudoparaphyses. Asci (32–)53–70 × (34–)41–51 µm (x = 54 × 45 µm, n=10), 8-spored, bitunicate, globose-subglobose, thick-walled, apedicellate, without a well-developed ocular chamber. Ascospores 26–29 × 12–18 µm (x = 28× 14µm, n=20), multi-seriate, conglobose, brown to dark brown, 1-septate, constricted at the septum, smooth-walled. Asexual state: hyphomycetous, Acrodesmis cestri . Conidiophores (59–)189–206 × 5–9 µm (x = 178 × 9 µm, n=10), formed on sexual ascoma, erect, straight or flexuous, elongated, dark brown, some branched at the apex, septate, thick-walled, smooth. Conidiogenous cells polyblastic, integrated, terminal, sympodial, oblong, brown to dark brown and rough. Conidia 11–15 × 4–6 µm (x = 13 × 5 µm, n=20), cylindrical to ovoid, elliptical or fusiform, rounded at the apex, slightly tapered at the base, aseptate, hyaline and smooth-walled ( Figs. 1 o–q ).

Material examined:— COSTA RICA. La Caja bei San Jose, on leaves of Cestrum macrophyllum (Solanaceae) , with its asexual morph: Acrodesmis cestri Syd. , 13 February 1925, H. Sydow ( GZU 157-80!, holotype).

Notes:— Allosoma was introduced by Sydow (1926) as a monotypic genus to accommodate Allosoma cestri found on leaves of Cestrum macrophyllum . Thereafter, A. quercifoliae Bat. & Nascim , A. arrabidaeae Bat. & J.L. Bezerra and A. indicum Tilak, S.B. Kale & S.V.S. Kale have been assigned to the genus (Index Fungorum 2013). Allosoma indicum occurs on dead stems ( Tilak and Kale 1969), while other species are found on leaves. von Arx (1963) placed Allosoma in Myriangiales, while Sivanesan (1984) categorized this genus under Englerulaceae , Capnodiales . Lumbsch & Huhndorf (2010) included Allosoma under Dothideomycetes, genera incertae sedis.

We examined and illustrated the type specimen of Allosoma and it shares common morphological characters with the generic type of Englerulaceae in having septate, irregularly to reticulately branched, hyphae, non-ostiolate ascomata, a hamathecium without pseudoparaphyses, obovoid to subclavate, globose to subglobose asci and fusiform, broadly ellipsoid to subobovoid, 1-septate, ascospores which are constricted at the septum. Therefore in this study we refer Allosoma in the family Englerulaceae based on morphological similarities with the generic type of Englerulaceae . Sydow (1926) also described the asexual state of Allosoma cestri ( Acrodesmis cestri ) which was found on the same leaves of Cestrum macrophyllum , but later Ellis (1967) accommodated it in Mycosphaerellaceae as Periconiella cestri . In our study we also observed the Acrodesmis cestri state ( Periconiella cestri ) on the herbarium material in close association with the sexual ( Allosoma cestri ) state. Although we cannot unequivocally show that these are the same fungus we believe it is highly likely (see Fig. 1b, c ) and therefore we synonymise Acrodesmis cestri ( Periconiella cestri ) under Allosoma cestri .

Lichenotheliaceae Henssen, Syst. Ascom. 5: 137 (1986)

MycoBank: MB 81652

Henssen (in Eriksson & Hawksworth 1986) introduced Lichenotheliaceae for Lichenothelia and Lichenostigma and typified this family with Lichenothelia scopularia . The family is characterized as endolithic or epilithic when saxicolous, episubstratic or endokapylic when lichenicolous, perithecioid ascomata with interascal filaments without an ostiole, globose to broadly clavate, asci and 1-septate to muriform ascospores ( Hyde et al. 2013). Lumbsch & Huhndorf (2010) listed this family under Dothideomycetes, families incertae sedis, while Hyde et al. (2013) placed this family in a new order Lichenotheliales of the Dothideomycetes. Asexual states consist of black macroconidia, originating from the surface of superficial hyphae, immersed pycnidia in vegetative stromata and hyaline, non-septate and rod-shaped conidia ( Hyde et al. 2013).

Figures

FIGURE 1. Allosoma cestri (= Acrodesmis cestri) (GZU157-80, holotype). a. Herbarium material. b. Appearance of sexual and asexual states on leaf.c. Close-up of ascoma. d–f.Squash mount of ascomata.g–h. Immature and mature asci. i–j.Ascospores. k–m. Conidiophores with apical conidia. n. Conidiogenous cells. o–q. Conidia. Scale bars: b = 500 µm. c, k = 200 µm. d, e, g = 100 µm. f, l, m = 50 µm. h, n = 20 µm. i–j = 10 µm. o–q = 5 µm.