Tilletia micrairae R.G. Shivas, M.D. Barrett, R.L. Barrett & McTaggart

Description

Sori in some ovaries of an inflorescence, obovoid, more rarely broadly ellipsoidal or lemon-shaped, 0.5–1 × 0.7–1.2(–1.5) mm, covered by a thin greyish brown pericarp that ruptures
irregularly, exposing the black powdery mass of spores mixed with numerous sterile cells.

Spores globose, subglobose, ovoid or broadly ellipsoidal, 24–33(–37) × (22–)24–32 µm, yellowish to dark reddish or chocolate-brown, sub-opaque or opaque; wall 1.5–6.5 µm thick, including the densely situated warts, (1–)1.5–6 µm high, higher in yellowish brown spores than in darker spores; warts in yellowish brown spores acute or subacute, spiniform, in dark spores the warts are blunt or nail-headed, sub-hyaline, in surface view appearing as irregular subpolyangular spots, 10–15(–20) per spore diam, isolated or fusing into short, irregular rows or groups, 40–55 on the spore circumference, spore profile smooth due to the sheath in which the warts are embedded.

Sterile cells globose, subglobose, broadly ellipsoidal to slightly irregular, 12–33(–40) × 12–26 µm, sub-hyaline, content homogenous or usually with droplets; wall 1.5–7 µm thick, smooth.

Hosts
   
Host family: Poaceae
   
Host species: Micraira dunlopii Lazarides

Distribution

States & Territories: WA