Macalpinomyces digitariae Vánky & R.G. Shivas


Sori in some ovaries of an inflorescence, inconspicuous, ovoid, with a short acute tip, 1.0–1.5 mm long, 0.5–0.7 mm wide, ±hidden by the floral envelopes, at first covered by a thin pale brown peridium that ruptures irregularly exposing the dark brown semi-agglutinated to granular-powdery mass of spores mixed with sterile cells.

Spores solitary or in irregular groups, subglobose, ovoid, ellipsoidal to usually subpolyhedrally slightly irregular, 7.5–12.0 × 7.0–9.5 µm, yellowish brown; wall uniformly 0.5–0.8 µm thick, finely and rather densely echinulate; spore profile ±smooth to finely serrulate.

Sterile cells solitary or in irregular groups, ovoid, ellipsoidal to subpolyhedrally irregular, the same size or larger than the spores, 8–14 × 7–13 µm, pale yellowish brown; wall 1.0–1.5 (–2.0) µm thick, smooth.

Host family: Poaceae
Host species: Digitaria gibbosa (R.Br.) P.Beauv.


States & Territories: NT


Macalpinomyces digitariae is one of two smut fungi that occur on Digitaria gibbosa in Australia. The other, Sporisorium gibbosum, has sori in all spikelets of the inflorescence, as well as a columella and larger spores (9.5–13.5 × 9–13 µm).