Tufted, stemless or short-stemmed, densely-silky plant. Leaves firm-textured, leathery, dark-green, densely-silky beneath and often purple below, on stalks 10-60mm long; each leaf has three leaflets increasing greatly in size after flowering to 40mm across. One of the first Oxalis species to flower in autumn, it has solitary lilac flowers and yellow tubes which are hairy, 14-24mm long; the flowers are borne on delicate articulated stems, the stem has two opposite bracteoles at the articulated joint; flowers are produced rather ahead of the leaves.

Latin: truncus = ending abruptly, as if cut; referring to the leaflets which have a slight nip or cut at the top.