Tilletia australiensis R.G. Shivas, Cother, G.J. Ash, Jane D. Ray & Vánky

Description

Sori partly or completely destroying some ovaries of an inflorescence, inconspicuous, concealed by the coriaceous lemma and palea, initially covered by the thin membranous pericarp that ruptures irregularly releasing the black powdery spore mass mixed with numerous sterile cells.

Spores globose, subglobose, ovoid, broadly ellipsoidal or subpolyhedrally slightly irregular, 18–27 × 17–23 µm, pale to dark olivaceous brown or chocolate-brown, occasionally with a short or long narrow hyaline hyphal appendage; wall c. 2.5 µm thick, with blunt warts that, in surface view, appear as small darker rounded or polygonal areas, 10–16 per spore diameter, isolated or in some spores 2–several confluent, rarely forming short irregular rows; in optical median view 38–57 warts on the spore circumference, 0.5–1.0 µm high, embedded in a thin hyaline sheath; spore profile wavy or smooth due to the sheath.

Sterile cells globose, ovoid, ellipsoidal to irregular with slightly flattened sides, rarely with a short papilla or a hyphal appendage, 12–30 × 11–20 µm, hyaline, guttulate; wall slightly uneven, 1–3 µm thick, smooth or with a trace of ornamentation (intermediate forms).

Hosts
   
Host family: Poaceae
   
Host species: Oryza rufipogon Griff.

Distribution

States & Territories: NT

Comments

Tilletia australiensis differs from T. horrida, which occurs on cultivated rice (Oryza sativa) in Australia, by having smaller spores with shorter and more numerous warts.