Tilletia xerochloae R.G.Shivas, A.R.McTaggart & Vánky

Description

Sori in some ovaries in an inflorescence, ellipsoidal to lemon-shaped, 2–3 mm long, 1.5–2.0 mm wide, mostly hidden by the floral envelopes, green when immature, dark brown to black at maturity, splitting longitudinally from the apex to expose the black powdery mass of spores mixed with sterile cells.

Spores globose or subglobose or rarely broadly ellipsoidal, 21–28 (–30) × 21–27 µm, pale to dark chestnut-brown or even subopaque; wall 2.5–3.0 µm thick (incl. ornamentation), moderately densely and prominently low-echinulate, these, in surface view, appearing as darker rounded or slightly irregular spots c. 1–1.5 µm diam., 8–13 spots per spore diameter in optical median view appearing as 1.0–1.5 µm high spines, 36–48 on the spore circumference, embedded in a hyaline sheath equalling or slightly exceeding the top of the spines.

Sterile cells globose, subglobose, rarely broadly ellipsoidal or subpolyhedrally slightly irregular, 12–50 µm long, subhyaline to pale yellowish brown; wall 1.5–6 µm thick, 2–3 (–4)-layered, smooth or with traces of ornamentation, rarely with a hyaline papilla or also a narrow mycelial remnant.

Hosts
   
Host family: Poaceae
   
Host species: Xerochloa barbata R.Br.
Xerochloa imberbis R.Br
Xerochloa laniflora Benth.

Distribution

States & Territories: WA

Comments

Tilletia xerochloae is the only species in the genus which has been described on Xerochloa, although another species, T. opaca, occurs on Spinifex in the subtribe Spinificinae. Tilletia xerochloae has smaller sori and spores that are more regularly shaped and thinner-walled, with fewer warts per spore diameter than T. opaca.