Loosely cushion-forming, intricately branched subshrublet or a medium shrub 30-300cm tall. Leaves pale yellow-green, rarely glaucous, when fully developed consisting of three tough, spreading needle-like spiny lobes 1-3.5cm long, the central one entire, the laterals bent upwards and deeply bifid. Flowers usually monoecious, five to sixty per umbel on peduncles clear of the foliage, 2- 6cm high and pedicels 4-12mm long. Each flower greenish-yellow, up to 4.5mm wide, spring in the wild. Fruits also on the large side up to 9mm all round and narrowly winged. Chile and Argentina, as an important element of the Andean and in particular the Patagonian steppe, often dominant from the northern central cordilleras to the tip of the mainland at 40-3000m, depending upon latitude. It may hybridise with M. echinus.