Ustilago valentula Syd.


Ustilago enteropogonis Vánky


Sori destroying the inflorescence, or remnants of inflorescence branches and spikelets remaining attached apically, 15–40 mm long, 4–8 mm, often hidden by leaf sheaths, at first covered by a thin greyish membrane that flakes away exposing the dark brown powdery mass of spores and a central columella up to 20 mm long.

Spores subglobose, ellipsoidal to slightly irregular, 10.0–14.5 × 9–13 µm, yellowish brown; wall uniformly c. 1 µm thick, densely and minutely verruculose-echinulate; spore profile finely serrulate, in SEM moderately verrucose, densely and finely verruculose between the warts.

Host family: Poaceae
Host species: Enteropogon acicularis (Lindl.) Lazarides
Enteropogon ramosus B.K.Simon


States & Territories: NSW, QLD


Ustilago valentula is one of many smut fungi that share characteristics of Ustilago and Sporisorium. Although this species has a columella, we have retained it in Ustilago as the sori occupy the basal part of the uppermost leaf sheaths as bullate subepidermal swellings; the peridium seems to be composed of host tissue; the spores are uniformly globose; and spore balls were not seen. Sterile cells as described by Sydow (1937) were not observed, although small hyaline cells, which may have been teliospore initials, were occasionally seen on sporogenous hyphae. Ustilago valentula has rarely been collected, perhaps because host plants are systemically infected making identification of the host difficult.