Ustilago bullata Berk.

Synonyms

Ustilago asprellae G. Cunn.

Description

Sori completely destroying the spikelets, leaving intact the apical part of some floral envelopes of the distal flowers and their awns, 5–15 mm long, 1–2 mm wide, often extending down the floral axis and becoming confluent, occupying the whole spike, then up to 40 mm long or longer, at first lead-coloured, covered by a thin membrane of host origin which ruptures irregularly exposing the dark brown semi-agglutinated to powdery mass of spores which becomes scattered leaving the bare rachis of the inflorescence. Sori may also appear on the distal leaves as short or long bullate striae.

Spores globose, subglobose, ovoid or broadly ellipsoidal, 8.0–10.5 × 7–9 µm, olivaceous brown; wall uniformly c. 0.8 µm thick, in LM coarsely low-verrucose, spore profile wavy, in SEM densely verrucose-echinulate.

Hosts
   
Host family: Poaceae
   
Host species: Elymus scaber (R.Br.) Á.Löve

Distribution

States & Territories: ACT, NSW, SA, TAS, VIC