Tilletia narayanaraoana Mundk. & Thirum.

Description

Sori in some ovaries of a panicle, cylindrical, 2.5–6.0 mm long, 0.8–1.5 mm wide, partly hidden by the innermost floral envelopes that are often elongated, at first covered by a dark brown leathery smooth peridium that ruptures from its paler apex exposing the black semi-agglutinated to powdery mass of spores and sterile cells. Usually both florets of a spikelet developing sori.

Spores globose, subglobose, ovoid to broadly ellipsoidal, 20–28 × 16–25 µm, dark yellowish brown to chocolate-brown and opaque, with dense 1.5–3.0 µm long filiform warts, usually agglutinated into small irregular groups, in surface view showing as minute dark spots in groups, in optical median view appearing as irregularly wide and spaced groups with flattened tips, 20–28 on the equatorial circumference; in SEM the spore surface irregularly and finely labyrinthiform-ornamented.

Sterile cells globose, subglobose, ovoid, ellipsoidal to slightly irregular, 13–21 × 8–20 µm, pale yellowish or olivaceous brown; wall uniformly 1.5–3.0 µm thick, smooth to finely and densely verruculose.

Spore germination producing a holobasidium bearing a terminal whorl of 12–16 basidiospores that conjugate immediately.

Hosts
   
Host family: Poaceae
   
Host species: Panicum trachyrhachis Benth.

Distribution

States & Territories: NT

Comments

The spores of the Australian specimens are slightly larger and darker than those of the type, but they exhibit the same distinctive ornamentation.