Sporisorium exsertum (McAlpine) L. Guo

Synonyms

Cintractia exserta McAlpine
Sphacelotheca anthistiriae (Petch) L. Ling
Sphacelotheca exserta (McAlpine) Cif.
Sphacelotheca exserta
(McAlpine) W.Y. Yen
Sphacelotheca vryburgii Zundel
Ustilago anthistiriae Petch
Ustilago condigna Syd.

Description

Sori occupying entire racemes, 4–16 mm long, 1–2 mm wide, cylindrical but often with short adpressed lateral spikelet-like branches, at first covered by a yellowish brown peridium that flakes away exposing a central branched columella surrounded by a blackish brown agglutinated mass of large irregular readily disintegrating many-spored spore balls (of up to several hundred spores) mixed with small groups or chains of sterile cells.

Spores globose, ovoid to subpolyhedrally irregular, 6.0–9.5 × 5.5–8.0 µm, yellowish brown; wall uniformly 0.5–0.8 µm thick; ornamentation depending on initial position of the spore in a spore ball, from apparently smooth to very finely or distinctly and moderately densely punctate-verruculose.

Sterile cells subglobose to irregular, larger than the spores, 8–18 µm long, collapsed in old specimens, subhyaline; wall 1.0–1.5 µm thick, smooth.

Hosts
   
Host family: Poaceae
   
Host species: Themeda triandra Forssk.

Distribution

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

Comments

Sporisorium exsertum and S. walkeri are the two most commonly collected and widespread smut fungi on Themeda triandra in Australia. They occasionally occur on different plants at the same location.