Stem prostrate and rooting, us. < 1 cm. diam., terminating in tuft of ± erect lvs. Lamina submembr., c. 1-3 cm. × 8-20 mm., ovate, regularly shallowly crenate-dentate, base rounded, upper surface uniformly and rather closely covered with short hairs, hairs on undersurface confined to veins; petiole channelled, narrow, us. > lamina, with scattered to crowded hairs. Peduncle hairy, erect, much > lvs, rarely > 20 cm. tall in fr., us. with 2 or 3 ± sessile cauline lvs below floral bracts. Bracts in (1)-2-3 whorls, 2-5-(7) per whorl, subentire and decreasing in size upwards; hairs almost confined to margins. Pedicels up to as many as bracts in each whorl and longer, up to 3 cm. long, clad in flexuous tapering non-glandular hairs. Calyx-clefts all reaching almost to base; lobes c. 5-6 × 1 mm., entire, acute to subacute, hairs few to many, non-glandular. Corolla 15-20 mm. diam., hairs on outside of tube sts sparse or confined to base of posterior lobes.

DIST.: N. Coromandel Range (Te Aroha, M. Fowlds, 1952; Te Moehau), Kaimanawa, Ruahine and Tararua Ranges. Above bushline in damp places.

Type locality: Top of Ruahine Range. Type: K, Colenso, 1605.

The name O. colensoi has been variously applied and herbarium folders often contain a mixture of specimens. The sheet in the type folder at K has two groups of Colenso specimens, both from the Ruahines, and one group from Wairau Mountains, Travers, 1862. The Colenso specimens are all small with peduncles little > 5 cm. tall and not more than 2 fls per node; in their ovate, ± membr., hairy basal lvs, evenly divided narrow calyx-lobes and lack of glandular hairs they match the 5 Colenso specimens at W (including one numbered 1605) though these latter include some larger plants with 5 or occ. 7 fls per node. The Travers specimens at K differ in having glandular hairs on pedicel and calyx and match small states of O. macrophylla var. lactea. The selection of Colenso 1605 as the lectotype preserves current usage in that the name continues to apply to the North Id plant collected by Colenso; it might be argued that the Travers specimens agree better with the original description which records the sp. and the calyx as "glandular-pubescent".