Echinopsis chamaecereus is a species of cactus from Argentina. Synonyms include Chamaecereus silvestrii and Lobivia silvestrii. It is called the "peanut cactus". The cactus is known for its vivid red flowers, often produced in prolific quantities.
The peanuts cactus, Echinopsis chamaecereus is a very popular cactus with many crowded finger-like stems. Echinopsis chamaecereus young shoots somewhat resemble peanuts. With increasing age, however, the shoots of this cactus lengthen into cylindrical finger-like stems which are pale green, very soft and segmented lengthwise by 8 to 10 narrow, low ribs with broad, shallow indentations in between. The main stems are about 15cm (6 inch) long and 2cm (0.8 inch) in diameter and they tend to lie on the surface of the potting mixture with many much smaller branches distributed among them. Deep scarlet, cup-shaped flowers about 2.5cm (1 inch) wide are produced from the areoles in early summer. Individual flowers last about a day, but the flowering period extends for two to three weeks and Echinopsis chamaecereus will produce numerous blooms during early spring to early summer period under favourable conditions.