A shrub 1 to 2 ft high, with erect or spreading branches; stems more or less bristly. Leaves leathery, shortly stalked, dull green above, paler beneath, elliptic to elliptic-oblong or lanceolate-oblong, apiculate at apex, 4⁄5 in. to 12⁄5 long (occasionally to almost 2 in.), margins finely saw-toothed (sometimes coarsely so). Flowers in racemes up to about 3 in. long, borne at the apex of the shoots and in the uppermost of leaf-axils, the racemes sometimes branched; inflorescence-axis and pedicels downy. Calyx deeply lobed, the lobes ovate, acute, minutely toothed, Corolla urn-shaped, white and waxy, about 1⁄6 in. long. Fruit a capsule, surrounded by the persistent but dry calyx.
A native of the mountains of the South Island of New Zealand, but descending to near sea-level in the southern end of its range. It has never been common in British gardens but is striking in flower and should be hardy if introduced from a high altitude. There is a fine photograph of this species in Philipson and Hearn, Rock Garden Plants of the Southern Alps, Plate 55.
The following species, closely allied to G. rupestris, and included in it by other authorities, are recognised by Allan in Flora of Neiv Zealand (1966). In all of them the calyx remains dry in the fruiting stage.
G.colensoi Hook. f. G. rupestris var. colensoi (Hook. f.) Hook. f.; G. rupestris sensu Cheesem., in part – A native of the North Island of New Zealand, differing from G. rupestris mainly in its low-growing habit and its downy not bristly stems.
G. crassa Allan G. rupestris var. parvifolia Hook. f. – This species occurs in both islands of New Zealand and differs from G. rupestris in its stiffly leathery, smaller leaves, up to about 3⁄4 in. long at the most. In cultivation at Wakehurst Place, Sussex.
G. subcorymbosa Col. G. rupestris var. subcorymbosa (Col.) Burtt and Hill; G. rupestris sensu Cheesem., in part – Corolla glabrous within. Leaves usually less than 1 in. long. The inflorescences are sometimes branched. A native of the North Island of New Zealand and of the Aorere Valley in South Island (Nelson).