Anthracocystis setariae (McAlpine) McTaggart & R.G. Shivas

Synonyms

Sorosporium setariae McAlpine
Sporisorium setariae (McAlpine) Vánky & R.G. Shivas

Description

Sori destroying some or all spikelets in the inflorescence, ovoid to short-cylindrical, 2.5–7.0 mm long, 1–2 mm wide, partly hidden by the floral envelopes, at first covered by a pale brown peridium that ruptures from its apex exposing the black granular-powdery mass of spore balls and sterile cells surrounding 2–6 stout irregular flattened columellae c. the length of the sorus, narrowing toward the apex, often with short apical branches.

Spore balls subglobose, ellipsoidal, elongate or irregular, 40–100 (–170) × 25–70 (–110) µm, dark reddish brown, composed of tens to hundreds of spores that separate by pressure.

Spores subglobose, ellipsoidal to usually subpolyhedrally irregular, (7.5–) 8–13 (–14.5) × (6.5–)
7–12 µm, dimorphic. Outer spores dark yellowish brown; wall slightly uneven, 0.5–1.0 µm thick; free surface densely and finely verrucose-echinulate; spore profile wavy to finely serrulate. Inner spores pale yellowish brown, wall c. 0.5 µm thick, apparently smooth to finely and densely punctate.

Sterile cells few, solitary, globose to ovoid, 6–10 µm long, hyaline; wall 1–2 µm thick, smooth.

Hosts
   
Host family: Poaceae
   
Host species: Setaria apiculata (Scribn. & Merr.) Schumann
Setaria pumila (Poir.) Roem. & Schult. subsp. pumila
Setaria surgens Stapf

Distribution

States & Territories: NSW, NT, QLD, WA