Restiosporium flexuosum Vánky

Description

Sori in all nuts of an inflorescence, ovoid, flattened, with an acute tip, visible between the spreading floral envelopes, 1.5–2.5 mm long, 0.5–1.0 mm wide, filled with a dark brown powdery mass of ephemeral spore balls and spores. The fungus induces transvestism in the host.

Spores solitary when mature, globose, ovoid, ellipsoidal, elongate or subpolyhedrally irregular, rarely with short acute tips at the angles and narrow lines on the surface, 9–16 × 7–12 µm, pale olivaceous brown; wall ±uniformly 0.5–1.5 µm thick; in LM smooth, in SEM all spores finely and densely verruculose.

Hosts
   
Host family: Restionaceae
   
Host species: Desmocladus flexuosus (R.Br.) B.G.Briggs & L.A.S.Johnson

Distribution

States & Territories: WA

Comments

Two smut fungi, R. flexuosum and R. desmocladi, occur on Desmocladus flexuosus. Restiosporium flexuosum differs from R. desmocladi (type on Desmocladus elongatus) by the ephemeral spores balls, more rounded spores and thinner, finely and densely verruculose spore walls.