Sporisorium sehimicola Vánky

Description

Sori in the sessile, hermaphrodite spikelets, leaving intact the two glumes and the awned lemma, rarely also in the pedicelled, neuter spikelet. Young sori subcylindrical, 3–4 × 1.0–1.5 mm, covered by a brown, leathery peridium which ruptures irregularly at maturity disclosing the blackish brown, powdery mass of spores intermixed with groups of sterile cells. An evident, up to 1 cm long, simple or apically shortly ramifying, tapering columella is present. The distal part of the peridium often bears remnants of inner floral organs and aborted anthers.

Spores when mature single, subglobose, ovoid, ellipsoidal or irregular, 10–13 × (9.0–)9.5–11.0(–12.0) µm, olivaceous brown, with small remnants of sporogenous hyphae as bright spots; wall even, c. 1 µm thick including the densely situated, fine but evident spines, spore profile finely serrulate.

Sterile cells varying in shape and size, subglobose, ellipsoidal or irregular, 7–17 µm long, in irregular groups or sometimes single, hyaline; wall even, 1.0–1.5 µm thick, smooth.

Hosts
   
Host family: Poaceae
   
Host species: Sehima nervosum (Rottler) Stapf

Distribution

States & Territories: QLD

Comments

Sporisorium sehimicola is one of four species on Sehima in Australia, but it is the only one with ephemeral spore balls and sterile cells. It is represented by a single specimen that was collected at the type locality of S. nervosum, which also occurs on Sehima nervosum.