Microbotryum tenuisporum (Cif.) Vánky


Ustilago microspora (Speg.) Liro
Ustilago polygoni-punctati Savile
Ustilago tenuispora Cif.
Ustilago utriculosa var. microspora Speg.


Sori in swollen flowers, filled with a light brown dusty spore mass, protected by the ±intact perianths. Infection systemic; all flowers of an inflorescence affected.

Spores globose, subglobose to ovoid, rarely elongate, 7–12 (–13) × 7.0–10.5 µm, violet-tinted pale olivaceous brown; wall 1.5 µm thick, reticulate, 3–5 (–6) meshes per spore diameter; muri 0.8–1.2 µm high; in SEM interspaces with a ±smooth to very finely verruculose tuberculum.

Spore germination resulting in 4-celled basidia on which sessile basidiospores are produced laterally and apically.

Host family: Polygonaceae
Host species: Persicaria hydropiper (L.) Spach


States & Territories: NSW, QLD, VIC