Dictyosporium tetraseriale Goh, Yanna and K.D. Hyde
Index Fungorum number: 450674
Etymology: tetraseriale, referring to the conidia which usually consisting of 4 rows of cells.
Sexual morph: Undetermined. Asexual morph: Colonies on natural substratum in the form of compact sporodochia. Conidiophores subhyaline to pale brown, thin-walled, short, irregularly branched. Conidiogenous cells cylindrical, determinate. Conidia 24–40 × 14–20 µm (x̄ = 30.7 × 16.8 µm, n = 30), complanate, cheiroid, smooth-walled, medium brown, consisting of 24–38 cells, arranged in 4 rows which are inserted in a pale brown to brown, 2-3 µm diam., truncate basal cell. The cells comprising the central 2 rows are darker than those of the outer rows. The cells at the apical portion of the 2 central rows are slightly swollen and are darker than other cells of the conidium. The apical cells of the outer rows are provided with an appendage which is hyaline, thin-walled, cylindrical, measuring 24–35 × 3–8 µm.
Materials examined: HONG KONG, The University of Hong Kong campus, Lung Fu Shan, on dead fronds of Livistona chinensis (Arecaceae), 19 Oct. 1996, Yanna (HKU(M) 5327, holotype); ibid., Tai Po Kau Forest Stream, on submerged wood, 29 Dec. 1996, W.H. Ho and S.Y. Ho (HKU(M) 5914); ibid., on submerged wood bait of Machilus velutina (Lauraceae), 28 June 1997, W.H. Ho (HKU(M) 6121); ibid., on submerged wood baits of Pinus massonaina (Pinaceae), 27 June 1996 (HKU(M) 4585, 4586, 4587); BRUNEI DARUSSALAM, Temburong, Batu Apoi Forest Reserve, Sungai Belalong, Kuala Be1along Field Studies Centre, Sungai Sitam, on submerged wood, 24 Oct. 1996, W.H. Ho and KD. Hyde (HKU(M) 2930).
Notes: This species is distinct in having conidia regularly comprising 4 rows of cells in which the central rows are darker than the outer rows. It resembles D. alatum which also has conidia provided with apical clavate appendages in the outer arms. Dictyosporium alatum, however, has conidia which regularly comprise 5 rows of cells, and all the cells are of even colouration. Cultures of D. tetraseriale are deposited at HKUCC (Nos. 2152, 2153, 2756, 2757).
Freshwater distribution: Brunei (Goh et al. 1999), Hong Kong, China (Goh et al. 1999)
Goh TK, Hyde KD, Ho WH, Yanna (1999) A revision of the genus Dictyosporium, with descriptions of three new species. Fungal Divers 2:65–100
Figs. 57-65. Dictyosporium tetraseriale, from holotype (HKU(M) 5327). 57. Squash mount of sporodochium with conidia, 58-63. Conidia, with hyaline, clavate appendages at the apex. Note the darker colouration of the central rows of cells. 64, 65. Conidia in side view. Scale bars: 57 = 20 µm, 58-65 = 10 µm.