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Puccinia purpurea Cooke

Description
Uredinia mostly on lower leaf surface, on ellipsoidal brown spots up to 3 mm long, covered by the necrotic torn host epidermis, subepidermal, erumpent, linear, round or ellipsoidal, up to 3 mm long, brown; paraphyses peripheral or intrasoral, clavate or capitate, ca. 6 µm wide at base and up to 22 µm wide at apex, yellowish to reddish brown, up to 110 µm long, curved; wall 1 µm thick at base becoming thicker (up to 11 µm) and darker at the apex.

Urediniospores subglobose, cylindrical, ellipsoidal or obovoid, yellowish to reddish brown, 30‒43 × 20‒28 µm; wall even, 1.5‒3.5 µm thick, echinulate, with 5‒9 scattered germ pores.

Telia on leaves, on dark reddish to purplish brown linear to ellipsoidal spots, occasionally forming in the uredinia, mostly on lower surface, subepidermal, covered or surrounded by necrotic flaps of host epidermis, erumpent, dome-shaped, black.

Teliospores ellipsoidal, apex rounded, reddish brown, 36‒48 × 22‒31 µm; wall 2.0‒4.5 µm thick, 4‒8 µm at apex, smooth, pedicel persistent, pale brown, 6‒10 µm wide at apex, cylindrical; wall 1.5‒2.5 µm thick.

Hosts
Host family: Poaceae
Host species: Sorghum almum
Sorghum arundinaceum

Sorghum bicolor
Sorghum halepense
Sorghum sudanense
Sorghum verticilliflorum
Sorghum vulgare

Distribution
NSW, NT, QLD, WA

Comments
McAlpine (1906) regarded P. purpurea as an exotic species. It was first reported in Australia by Bailey (1892, cited in McAlpine). Puccinia purpurea is one of the two most important fungal leaf diseases of sorghum in Australia, having a significant impact on grain production (Ryley et al. 2002).

Highslide JS
Puccinia purpurea on Sorghum bicolor - BRIP 44674.
Scale bar = 1 cm.
Highslide JS
Puccinia purpurea on Sorghum bicolor - BRIP 44674.
Scale bar = 1 mm.
Highslide JS
Urediniospores of Puccinia purpurea on Sorghum bicolor - BRIP 44674.
Scale bar = 10 µm.
Highslide JS
Paraphyses of Puccinia purpurea on Sorghum bicolor sp. - BRIP 44674.
Scale bar = 10 µm.
Highslide JS
Teliospores of Puccinia purpurea on Sorghum bicolor sp. - BRIP 44674.
Scale bar = 10 µm.