Type: Rust and Smut Fungi; Description: Spermagonia solitary or in groups, erumpent, rusty brown, minute; on both sides of leaves and on twigs. Uredinia rusty brown, minute. Urediniospores clavate, 35–50 5 20–25 μm, yellowish brown, verrucose. Telia rusty brown, minute, up to 0.5 mm in diameter, pustulate, rupturing the epidermis and often confluent, forming cankers up to 1 cm long; producing large numbers of rusty brown teliospores which, in wet weather, form a mucilaginous mass binding the pinnules together. Teliospores two on one sporophore, which has a lateral vesicle; teliospores globose to subglobose, 23 × 29 μm, ochraceous to fulvous, smooth; vesicle globose, 22 μm in diameter, hyaline.

Distribution: Northland, Auckland, Waikato, Bay of Plenty, Rangitikei, Wanganui, Wellington, Gisborne, Hawkes Bay.; 1st Record: Gadgil & Dick (2000b).

Significance: Infected leaves and twigs are killed, causing partial dieback of the crown. Developing spring flush of infected A. mearnsii becomes distorted and chlorotic. The rust has potential for being an important disease if host species are planted on a large scale.; Host(s): Acacia dealbata, A. mearnsii.