The performance of 55 Lotus pedunculatus Cav. and 33 Trifolium repens L lines of diverse type and origin was assessed on acid, infertile soils on the East Otago Plateau at 3 sites representing an altitudinal sequence of increasing severity of climate. Among the L pedunculatus lines, a diploid NZ selection 04701 showed the best combination of attributes with high herbage yields, moderate rhizome spread at the highest sites and considerable tolerance to out-of-season frosting. G4701, its tetraploid equivalent G4702 and a selection from within the cultivar 'Grasslands Maku' for rapid germination at low temperatures, produced the highest yields averaged over the 3 sites in the altiludinal sequence. The use of these lines is likely to enhance the role of lotus in tussock grassland pasture systems. Within white clover, a hybrid line C5413. which has been.included in the pre-release Southern white clover cultivar G26. performed well, indicating that it has wide adaptability for both fertile lowland and low-fertility hill and high country situations on the southern South Island. The Southland Selection C5844, which is derived from Southland ecotypes, had the best combination of attributes for the East Otago Plateau. This selection merits serious consideration for release as a 'Tahora-like' cultivar for moist, infertile hill and high country in the southern South Island. Keywords: Trifolium repens, Lotus pedunculatus. evaluation, herbage yield, spread, dominance, frost damage, South Island.