Canalisporium pulchrum (Hol.-Jech. & Mercado) Nawawi & Kuthub., Mycotaxon 34: 481 (1989)

Index Fungorum number: IF 125433

Saprobic on submerged wood. Asexual morph: Sporodochia scattered, punctiform, pulvinate, granular, black, shining. Mycelium mostly immersed, consisted of branched, thin-walled, hyaline to pale brown hyphae. Conidiophores up to 75 μm long, micronematous, mononematous, septate, unbranched, constricted at septa. Conidiogenous cells 4–6.5 × 4–4.5 μm (x̅ = 5.5 × 4.4 μm, n = 10), holoblastic, monoblastic, terminal, determinate, subcylindrical, hyaline, smooth, thin-walled. Conidia 32–46 × 15–22 μm (x̅ = 43 × 19 μm, n = 20), solitary, acrogenous, ellipsoidal to obovoid, narrowly to broadly subcylindrical, muriform, smooth, brown to dark brown, with two straight columns of vertical septa and 5–6 rows of transverse septa, constricted at the septa, darkened and thickly banded at the septa, cuneiform, pale brown to subhyaline, with single basal cell. Sexual morph: Undetermined.

Culture characteristics – on PDA, colony irregular, 8 mm in 55 days at 25 °C, dark grey from above, black from below, surface rough, raised, felty wooly, fairly dense.

Material examined – Thailand, Songkhla Province, Hat Yai District, Chestnut Hill, on submerged wood, 10 May 2018, W. Dong, hat463-1 (MFLU 18-1563), living culture MFLUCC 18-1402; ibid., hat463-2 (HKAS 105047), living culture KUMCC 19-0066.

GenBank numbers – ITS: MW131989, LSU: MW132064.

Known distribution (based on molecular data) – Thailand (Sri-indrasutdhi et al. 2010, this study).

Known hosts (based on molecular data) – Alstonia scholaris (Sri-indrasutdhi et al. 2010)

Notes – Our freshwater collection (MFLUCC 18-1402) clusters with five Thai strains of Canalisporium pulchrum with high bootstrap support (Fig. 63). The isolate MFLUCC 18-1402 resembles the holotype of C. pulchrum (PRM 831528) in all aspects, such as conidial shape, size and septation (Holubová-Jechová & Mercado Sierra 1984). Canalisporium pulchrum occurs on submerged or rotten wood in many countries and shows a wide range in conidial dimensions (Goh et al. 1998). However, the real identities of those collections have not been supported by molecular data. We provide sequence data and description for an additional Thai specimen MFLUCC 18-1402 collected from freshwater.

Canalisporium pulchrum (MFLU 18-1563, new collection). a Colonies on submerged wood. b Immatured conidium with conidiophore. c Matured conidium with conidiophore. d–f Conidia. g Germinated conidium. h, i Colony on PDA (left-front, right-reverse). Scale bars: b = 15 μm, c, e, f = 20 μm, d, g = 50 μm.