Sporisorium warambiense M. Piatek & R.G. Shivas

Description

Sori in the ovaries, cylindrical, approx. 4 mm long and 2–3 mm wide, partly hidden by the floral envelopes (glumes), initially covered by a leathery, pale brown peridium which during maturity ruptures from the apex, exposing a dark brown, semi-agglutinated to powdery mass of spore balls surrounding three simple, stout, narrowing columellae; columellae somewhat shorter than the length of the sorus.

Spore balls dark reddish-brown, under pressure readily disintegrating into single spores, subglobose, ellipsoidal and somewhat irregularly polyhedral, 58–90 × 50–70 µm, composed of tens of spores.

Spores subglobose, ellipsoidal to irregular, usually more or less polyhedral, (9.5–)10–13(–14) × 9–11(–12.5) µm (av. ± SD, 11.7±1.2 × 10.2±0.9 µm), dimorphic; outer spores reddish-brown, wall even, approx. 0.5–1.0 µm thick, prominently densely verruculose in LM and SEM, especially on the free surface, spore profile wavy to finely serrulate; inner spores yellowish-brown, wall even, approx. 0.5 µm thick, moderately finely punctate in LM, finely verruculose in SEM, spore profile almost smooth.

Sterile cells absent.

Hosts
   
Host family: Poaceae
   
Host species: Xerochloa laniflora Benth.

Distribution

States & Territories: WA

Comments

Sporisorium warambiense is very similar to S. xerofaciculatum, which also oocurs on Xerochloa in Western Australia. It differs in that S. xerofasciculatum has sterile cells and smaller spores that are less densely verruculose. Further collections will help determine if these differences warrant separation of these taxa or whether it merely indicates variation in a single species.