0. Unknown.
II. Uredosori erumpent, scattered, bullate, pulverulent, ferruginous, elliptical, 1 mm. diam. Spores shortly elliptical or obovate, 35-40 x 22-25 mmm.f ; epispore pallid ferruginous, 1.5-2 mmm. thick, except at the apex where thickened to 6 mmm. and deeper in colour, finely and densely echinulate; germ pores inevident.
III. Teleutosori erumpent, scattered, elliptical, 1-4 mm. long, bullate, pulverulent, chestnut-brown, surrounded by the ruptured epidermis. Spores subclavate or elliptical, 28-48 x 17-24 mmm. ; apex rounded, not or scarcely thickened, base attenuate, less commonly rounded, basal cell larger and slightly narrower; not or slightly constricted at the septum; epispore chestnut-brown, 2 mmm. thick, finely and sparsely verrucose ; pedicel deciduous, hyaline, fragile, to 20 x 6 mmm. ; germ pore of the upper cell apical or less frequently towards septum, basal pore immediately above the pedicel or between the septum and the pedicel, both conspicuous and occasionally papillate.
X. Mesospores rare, elliptical or obovate, 26-32 x 16-20 mmm.

The host is endemic and confined to the mountain regions of the South Island (Cheesem. 1925, p. 291).
This species differs from P. Rostkoviae Speg. on Rostkovia grandiflora in South America, in the epispore of the teleutospore being verrucose, not smooth, and in the absence of paraphyses and presence of uredospores.

Host: Rostkovia gracilis Hook. f. Mt. St. Arnaud, Nelson, 1,800 m., 2/28. H. H. Allan! Type.

Only the type collection from the South Island on this endemic rush [Rostkovia gracilis] is in the herbarium of Plant Diseases Division, Auckland.