Digitodesmium heptasporum L. Cai & K. D. Hyde
Etymology: heptasporum, referring to the conidia with 7 rows of cells.
Holotype: HKU(M) 17158
Sexual morph: Undetermined. Asexual morph: Sporodochia on natural substratum 150–300 µm diam, punctiform, scattered, grey to dark brown, granular. Mycelium mostly immersed, composed of brown, smooth, thin-walled, septate, branched hyphae. Conidiophores semi-macronematous, mononematous, pale brown, smooth, thin-walled, unbranched, cylindrical, short, flexuous, deteriorating at conidial maturity. Conidiogenous cells monoblastic, integrated, pale brown, smooth, thin walled, cylindrical, terminal, determinate. Conidial secession schizolytic. Conidia 50–75 × 32.5–70 µm (x̄ = 61 × 50.5 µm, n = 25), cheiroid, cell rows arranged in several layers, pale brown, smooth, euseptate, holoblastic, solitary, consisting of 70–110 cells arranged in (6)–7 rows. Rows mostly separating at the apex, united by a 5–6.5 µm wide, pale brown, cubical, truncate basal cell. Each row of cells 47–67.5 × 7–8.7 µm, consisting of 11–17 cells, discrete, unbranched, cylindrical, with conspicuous pores in the septa, apical cells narrower than middle cells and mostly recurved, conidial appendages absent. (Cai et al. 2003)
Material examined: Holotype, CHINA, Yunnan, Xishuangbanna, Menglun, a small stream, on submerged wood, 21 June 2002, L. Cai, HKU(M) 17158.
Freshwater distribution: Yunnan, China (Cai et al. 2003)
Cai L, Zhang KQ, McKenzie EHC, Hyde KD (2003) New species of Dictyosporium and Digitodesmium from submerged wood in Yunnan, China. Sydowia 55:129–135
Figs. 12–17. Interference contrast micrographs of Digitodesmium heptasporum (from holotype). 12, 13. Squash mount of sporodochium with conidia, 14–17. Conidia. Note the conspicuous septal pores (small arrows). Scale bars: 12, 13 = 40 µm, 14–17 = 20 µm. (Cai et al. 2003)