Sporisorium exsertiformum Vánky

Description

Sori occupying the racemes, irregularly cylindrical, to 10 mm long, 0.5–2.0 mm wide, at first covered by a thick yellowish brown peridium that ruptures irregularly exposing the dark brown semi-agglutinated to powdery mass of spores mixed with sterile cells and a central columella of host origin. Columella simple or with 1 or 2 short adpressed branches, 5–12 mm long, usually slightly curved, tapering toward the apex.

Spores in loose many-spored balls, solitary when mature, globose, subglobose to broadly ellipsoidal or slightly irregular, 6.5–9.5 × 6.0–8.5 µm, dark reddish brown; wall relatively thick, 1.5–2.5 µm, finely and moderately densely punctate-verrucose.

Sterile cells subglobose to ovoid, usually collapsed, 10–22 µm long, solitary, in small groups or short chains, subhyaline; wall 1.5–2.5 µm thick, smooth.

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

Distribution

States & Territories: NT, QLD

Comments

Sporisorium exsertiformum has a thicker spore wall than S. exsertum, which it otherwise resembles in sorus characters and spore dimensions. The spore wall in S. exsertum is comparatively thin (0.5–1.5 µm).