VIRTUAL MYCOTA: NZ Fungi Identification: Moellerodiscus griseliniae

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Moellerodiscus griseliniae

Synonyms

Ciboria griseliniae

Biostatus

Present in region - Indigenous. Endemic

Images (click to enlarge)


Caption: Fig. 3 Moellerodiscus griseliniae (A-B, PDD 64239; C-E,PDD 70062). A, macroscopic appearance with apothecia in large, irregularly shaped stromatic areas; B, macroscopic appearance, detail of a	Caption: Fig. 4 Moellerodiscus griseliniae (PDD 70061). A, ascus containing ascospores; B, released ascospores; C, distribution of collections examined. Scale bar A, B = 20 µm.

Article: Johnston, P.R. (2002). Three new species of Moellerodiscus (Helotiales, Rutstroemiaceae) from New Zealand. New Zealand Journal of Botany 40(1): 105-115 (http://www.rsnz.org/publish/abstracts.php).
Description: DESCRIPTION: Apothecia developing on both upper and lower surface of fallen leaves, associated with irregularly shaped stromatic areas (often with several areas on a single leaf), leaf surface in these areas slightly blackened, margin marked by a narrow black zone line. Apothecia erumpent from beneath epidermis, arising from basal stroma comprising textura intricata of tightly packed hyphae c. 5 µm diam., with walls thick, gelatinous, dark brown, with scattered groups of crystals 40-60 µm diam. at base of stroma and in surrounding host tissue; hyphae within host tissue 5 µm diam. with walls gelatinous, hyaline, completely replacing leaf tissue, except for the more or less intact epidermis and upper layer of hypodermal cells. Apothecia up to 4 mm diam.,cupulate, short stipitate to stipitate; disc plane, dark red when fresh, very dark red to black when dry; receptacle finely roughened, concolorous with disc, when dry often with small, scattered clumps of bright rusty brown material; stipe more or less cylindric, with black base. Ascomata release bright pinkish red ("vivid Red", Kelly 1965) pigment in KOH. Ectal excipulum 50-65 µm thick, textura globosa to textura angularis with elements oriented more or less perpendicular to receptacle surface, comprising short-cylindric, angular or globose, 6-12 µm diam. cells with walls thick, hyaline, refractive, with outermost cells 5-11.5 µm diam., more or less free, containing red-brown pigment. Medullary excipulum textura intricata of loosely packed hyphae 3-4.5 µm diam. with walls thin, finely encrusted, pale brown, nongelatinous. Subhymenium a dense textura intricata comprising hyphae 3-5 µm diam. with walls pale brown, thin to slightly thickened, nongelatinous. Paraphyses 1.5-2 µm diam., apex slightly swollen to 3-4 µm diam., unbranched, about same length as asci. Asci (75-)80-100(-110) x (9.5-)10.5-11.5(-12) µm, cylindric to subclavate, tapering slightly to subtruncate apex, wall thickened at apex, apical pore amyloid with small but intense reaction on inside edge of wall, 8-spored, spores overlapping uniseriate, extending 70-75 µm from ascus apex. Ascospores (10.5-)11.5-12.5(-14) x (4.5-)5-6(-6.5) µm (x- 12 x 5.75 µm, n = 45), ovate to broad elliptic, more or less symmetrical, each end broadly rounded, slightly curved, sometimes slightly wider in upper half, 0-septate, wall hyaline, thin,smooth.
Notes: ETYMOLOGY: Refers to host substrate.
NOTES: M. griseliniae is macroscopically similar to M. coprosmae (see Discussion and Table 1). Lanzia griseliniae, another discomycete which also occurs on fallen Griselinia leaves, does not appear to be as common as C. griseliniae, although the two species can sometimes be found at the same site. L. griseliniae differs in apothecial colour: when fresh the disc is mustard-yellow and the receptacle pale yellow-brown, when dry the disc is more variable in colour, from a blackish brown to deep orange brown (TAUPO: Tongariro National Park, Ruapehu,on Griselinia littoralis, J. M. Dingley, 20 Oct 1949, PDD 19046. NELSON: vic. Karamea, Kohaihai, Nikau Walk, on Griselinia lucida, P. R. Johnston D1041, 11 May 1994, PDD 64240. STEWART ISLAND: Mason Bay, on Griselinia littoralis, P. R.Johnston D1406 & E. H. C. McKenzie, 11 May 1994,PDD 70058). The two species also differ in apothecial structure, and ascospore size and shape (see description in Spooner 1987). Collections very similar to L. griseliniae have also been found on Pseudopanax crassifolius, Metrosideros excelsa, andM. umbellata (unpubl. data).