Langdonia fraseriana (Syd.) Vánky

Synonyms

Sorosporium fraserianum Syd.
Sporisorium fraserianum (Syd.) Vánky

Description

Sori in the ovaries, inconspicuous, ovoid or asymmetrically fusiform, 2–6 mm long, 1.0–1.5 mm wide, partly hidden by the floral envelopes, at first covered by a green, later brown pericarp that ruptures laterally exposing the blackish brown powdery mass of spore balls and spores; usually all ovaries of the inflorescence are affected, but some ovaries or inflorescence branches can escape infection. Columella and sterile cells absent.

Spore balls irregular, 35–60 µm (or larger?), readily disintegrating.

Spores globose, subglobose, ellipsoidal or slightly subpolyhedrally irregular, 5.5–8.0 × 4.5–6.0 (–6.5) µm, yellowish brown; wall c. 0.5 µm thick, finely and densely punctate-verruculose, the warts usually more pronounced on one side or in a restricted area of the spore surface where the spore profile may be finely serrulate; opposite side of the spores often ±smooth.

Hosts
   
Host family: Poaceae
   
Host species: Aristida caput-medusae Domin
Aristida contorta F.Muell.
Aristida leptopoda Benth.
Aristida nitidula S.T.Blake ex J.M.Black
Aristida personata Henrard
Aristida ramosa R.Br.
Aristida strigosa (Henrard) S.T.Blake ex J.M.Black
Aristida vagans Cav.

Distribution

States & Territories: NSW, NT, QLD, SA

Comments

This is one of four species of Sporisorium known to occur on Aristida in Australia. The sori of L. fraseriana are initially green, and this feature is often visible, even in herbarium specimens. It has spores that are more rounded and less polyhedral than those of L. aristidae which also has small spores less than 10.5 µm long.