Sporisorium wynaadense (Sundaram) Vánky & R.G. Shivas

Synonyms

Ustilago wynaadensis Sundaram

Description

Sori at first appearing as grey swellings on the basal part of the glumes, later destroying the inner part of the spikelets, transforming them into 2–4 mm long ellipsoidal or conically acuminate bodies, ±hidden by the glumes, initially covered by a peridium that ruptures exposing the brown powdery mass of spores and sterile cells surrounding a short simple central columella.

Spores when mature solitary, subglobose, ellipsoidal or elongate, sometimes lacrymiform, often slightly irregular with a flattened side, 6–9 × 4.5–7.0 µm, olivaceous brown, paler on one side; wall unevenly thick, c. 0.5–0.6 µm on the darker side, c. 0.2–0.3 µm on the pale side, smooth.

Sterile cells solitary, in pairs or in small groups; individual cells c. the size of the spores or larger, globose to irregular, 6–14 µm long, hyaline; wall thin, c. 0.5 µm, smooth.

Spore germination resulting in 4-celled cylindrical basidia 25–40 × 3.5–5.0 µm producing lateral and terminal ovoid to ellipsoidal basidiospores measuring 5–11 × 2–4 µm.

Hosts
   
Host family: Poaceae
   
Host species: Sarga leiocladum (Hack.) Spangler
Sorghum sp.

Distribution

States & Territories: NT, QLD

Comments

Among the smut fungi that occur on Sarga and Sorghum, S. wynaadense most closely resembles Ustilago porosa Langdon as both have spores that are smooth and darker on one side (Vánky & Shivas, 2001). However, S. wynaadense has sori that first appear as swellings at the basal part of the glumes, similar to those produced by U. bullata Berk. Furthermore,
S. wynaadense is restricted to the spikelets, whereas U. porosa destroys the entire inflorescence, leaving behind a typical porous structure of host tissues.