Portulaca grandiflora (Moss-rose Purslane or Moss-rose), is a flowering plant in the family Portulacaceae, native to Argentina, southern Brazil, and Uruguay. It is a small, but fast-growing annual plant growing to 30 cm tall, though usually less. The leaves are thick and fleshy, up to 2.5 cm long, arranged alternately or in small clusters. The flowers are 2.5–3 cm diameter with five petals, variably red, orange, pink, white, and yellow.

Numerous cultivars have been selected for double flowers with additional petals, and for variation in flower color, and it is widely grown in temperate climates as an ornamental plant for annual bedding or as a container plant.
two new natural betaxanthins that occur in the flowers of Portulaca grandiflora. The first, portulacaxanthin II, was shown to be the tyrosine-immonium conjugate of betalamic acid and the second, portulacaxanthin III, the glycine-immonium conjugate of the same chromophore.