Sporisorium iseilematis-ciliati Vánky

Description

Sori occupying the entire raceme, these agglomerated in witches’ brooms within the inflorescence; individual sori ovoid or cylindrical, 3–6 mm long, 1–2 mm wide, at first covered by a thick brownish peridium that dehisces from its apex exposing the dark brown powdery mass of spore balls, spores, sterile cells and a simple central columella.

Spore balls loose, many-spored, readily separating into single spores.

Spores subglobose, broadly ellipsoidal to slightly irregular, subpolyhedral, 9.5–13.0 × 8.0–10.5 µm, yellowish brown; wall uniformly 0.5–1.0 µm thick, finely and densely punctate-verruculose.

Sterile cells solitary, in pairs or in irregular groups, globose, ovoid or irregular with 1 or 2 flattened sides, 8–16 × 7–14 µm, subhyaline; wall 1–2 µm thick, smooth.

Spore germination resulting in 4-celled basidia of 28–40 × 2–3 µm on which numerous ovoid to long-ellipsoidal basidiospores, 4–8 (–12) × 1.5–2.5 µm, are produced on short lateral and terminal sterigmata that bud successively, developing yeast colonies.

Hosts
   
Host family: Poaceae
   
Host species: Iseilema ciliatum C.E.Hubb.
Iseilema fragile S.T.Blake

Distribution

States & Territories: NT, WA

Comments

Sporisorium iseilematis-ciliati is unlike other species of Sporisorium that infect Australian Iseilema in that it produces sori in witches’ brooms.