Chlorociboria metrosideri P.R.Johnst., 2021

Johnston, Peter R., Park, Duckchul, Smith, Matthew E., Mujic, Alija B. & May, Tom W., 2021, Brahmaculus gen. nov. (Leotiomycetes, Chlorociboriaceae), MycoKeys 80, pp. 19-43 : 19

Chlorociboria metrosideri P.R.Johnst. sp. nov. Figure 7

Typification.

New Zealand - Bay of Plenty • vic. Rotorua, Tarawera Falls (-38.1573, 176.5193); on fallen leaves Metrosideros excelsa ; P.R. Johnston (D2565) leg.; 16 May 2019; PDD 116740 - holotype; ICMP 23410 - ex type culture.

Etymology.

Refers to the host substrate of the known specimens.

Diagnosis.

Phylogenetically a Chlorociboria , differs in developing on dead leaves rather than wood and in the asci being 4-spored when mature.

Description.

Apothecia developing on partly decomposed fallen leaves, not associated with pigmentation of substrate. Apothecia less than 1 mm diam., sessile, with short, matted hairs around the margin, hymenium yellow. Hairs 20-45 × 4 µm, cylindric, walls thin, roughened. Apothecium in vertical section with ectal excipulum 30-40 µm wide, comprising short, broad-cylindric cells 5-7.5 µm diam., with walls hyaline, slightly thickened, rows of cells arranged at a high angle to the receptacle surface near the base of the cup, more parallel to the surface near edge of cup; medullary excipulum of narrow-cylindric cells with thin walls. Paraphyses 2-3 µm diam., taper slightly and gradually to rounded apex, extending 5-10 µm beyond asci. Asci 40-55 × 5.5-7 µm, cylindric, tapering slightly to broad, subtruncate apex, wall thickened at apex with amyloid pore extending as two narrow, parallel bands extending through the wall, initially with 8 spores, 4 spores aborting and 4-spored at maturity, crozier present. Ascospores 7.5-9.5 × 2.5-3.5 µm (average 8.3 × 3.1 µm, n = 20), oblong-elliptic, tapering to rounded ends, one side flat in side view, widest point towards one end, 0-septate, hyaline.

Additional specimen examined.

New Zealand - Auckland • Rangitoto Island, Kidney Fern Glen; -36.805544, 174.860064; on fallen, partly rotten Metrosideros excelsa leaves; P.R. Johnston (D2329) leg.; 23 Apr 2012; PDD 102723.

Notes.

The substrate in both specimens was partly rotted leaves. It is possible that this fungus has a broader host range as most host-specialised, leaf-inhabiting Leotiomycetes are found on recently fallen leaves of their preferred host. Cultures are slow growing (on PDA, 9 mm after 8 weeks) with sparse mycelium and pale brownish pigmentation, remaining sterile.

Figures

Figure 7. Chlorociboria metrosideri (PDD 116740) A fresh apothecia B margin of receptacle in vertical section C surface of receptacle in squash mount showing rough-walled hairs D apex of asci and paraphyses E immature ascus with 8 spores, and mature asci with 4 spores. Scale bars: 0.1 mm (A); 20 µm (B, C); 10 µm (D, E).