Host: Olearia lacunosa Hook. f. Mt. Arthur, Nelson, 1,300 m. 2/28. G.H.C. Type. Mt. Rangitaipo, Westland, 1,200 m. 2/28. G.H.C. Mt. Trovatore, Westland, 1,000 m. 2/28. G.H.C. Mt. Mantell, Westland, 1,000-1,500 m. 2/28. G.H.C. Alecs' Knob, Franz Josef Glacier, Westland, 1,000 m. 2/28.. G.H.C.

0. Pycnia in small, scattered, epiphyllous, orbicular groups: seated on discoloured spots, immersed.
I. Aecidia orange, in small scattered epiphyllous groups of 3-7,, often on the mid-rib, seated on discoloured spots. Peridia cylindrical, standing above the leaf surface 1.5 mm., 0.3-0.5 mm. diameter, margins eroded, finally lacerate. Spores shortly obovate, subglobose or polygonal, 24-30 x 16-22 mmm. ; epispore hyaline, 1 mmm. thick,, covered with densely packed angular warts, appearing reticulate-areolate in consequence.
II. Uredosori scattered, hypophyllous, orange, fading to sulphur-yellow, crowded in the vicinity of the mid-rib, orbicular, 0.5-1.5 mm.. diam., pulverulent, naked. Spores fusiform, clavate or seldom elliptical, pointed at one or both ends, 40-56 x 16-20 mmm. ; epispore hyaline, smooth, 1.5 mmm. thick, thickened apically to 4 mmm. ; germ pores absent, replaced by odd scattered thin places in the wall; mixed with numerous hyaline, cylindrical paraphyses.
III. Teleutosori similar to and mixed with the uredosori, sulphur-yellow. Spores elliptical or clavate, 80-100 x 20-30 mmm. ; apex rounded, not or scarcely thickened, basal cell nearly twice as long as the upper, and narrower; constricted at the septum; epispore tinted brown, 1 mmin. thick, smooth; pedicel persistent, hyaline, to, 140 x 8 mmm. ; germ pore of the upper cell apical, basal pore immediately beneath the septum, both obscure; immixed with numerous: hyaline cylindrical paraphyses.
X. Mesospores rare, elliptical or obovate, 30-50 x 18-26 mmm.

The host is endemic and fairly widely distributed through the^, South Island, but confined to the Tararuas of the North Island (Cheesem. 1925, p. 922).
This species possesses many peculiar features not present in any other New Zealand species; the uredosori are deeply embedded in the host tissues, when they appear similar to aecidia, but as the spores are not in chains, nor enclosed within peridia, they cannot be confused with such. The most peculiar feature is that the uredospores are smooth, a character rare indeed for this spore stage in the Uredinales. Another peculiarity is that the uredosori are present in the cycle, the.only example in which the complete cycle is known in New Zealand Olearia and Senecio inhabiting species. The teleutospores germinate immediately on reaching maturity, and arise from the uredosori.

Cunningham (1931a) stated that the host [Olearia laetmosa] is endemic and widely distributed throughout the South Island but confined to the Tararua Ranges in the North Island. The rust is confined to the South Island.

Type: Rust and Smut Fungi; Description: Spermagonia in small, scattered, circular groups, on discoloured spots; on the upper surfaces of leaves. Aecia in small, scattered groups, orange, on discoloured spots; on the upper surfaces of leaves. Aeciospores obovate to polygonal, 24–30 × 16–22 μm, hyaline, densely covered with angular warts. Uredinia scattered, rounded, orange fading to pale yellow, 0.5–1.5 mm in diameter; on the lower surfaces of leaves. Urediniospores fusiform, 32–56 × 16–20 μm, smooth, hyaline. Telia similar to and mixed with the uredinia, pale yellow. Teliospores elongate elliptical, 1-septate, 60–98 × 18–30 μm, smooth, light brown, almost hyaline; pedicel persistent.

Distribution: Wellington, Nelson, Buller, Westland.; 1st Record: Cunningham (1928).

Significance: None.; Host(s): Olearia lacunosa.