Stollia ewartii (McAlpine) McTaggart & R.G. Shivas


Macalpinomyces ewartii (McAlpine) Vánky & R.G. Shivas
Ustilago ewartii
Ustilago sorghi-stipoidei L. Ling


Sori in considerably swollen ovaries, only a few in each inflorescence infected, obovoid, with a tapering basal part and a shortly acute tip with remnants of the styles, more rarely lemon-shaped, 8–15 mm long, 4–10 mm, covered by a thick initially green, later brown peridium that ruptures at maturity exposing the brown powdery mass of spores mixed with groups of sterile cells.

Spores globose, subglobose or ellipsoidal, 9–15 × 9.0–14.5 µm, yellowish brown; wall uniformly thick, with dense conical spines 0.5–1.5 µm high and 0.5–1.0 µm wide at their base.

Sterile cells in large loose irregular groups; individual cells globose, ovoid, ellipsoidal to slightly irregular, 8–16 × 8–13 µm, hyaline; wall uniformly 0.5–0.8 µm thick, smooth; contents homogenous.

Spore germination resulting in septate basidia of variable length composed of numerous cells producing lateral and terminal 3–6 µm long fusiform basidiospores often in chains of 3 or more.

Host family: Poaceae
Host species: Sarga intrans (F.Muell.) Spangler
Sarga plumosum (R.Br.) Spangler
Sarga timorense (Kunth) Spangler


States & Territories: NT, WA


Stollia ewartii is widespread and common on annual sorghum (Sarga timorense). The immature sori are often conspicuous by their green colour and pendulous habit. Occasionally, host plants can be infected by both S. ewartii and Sporisorium porosum.