Alstroemeria, commonly called the Peruvian Lily or Lily of the Incas, is a South American genus of about 50 species of flowering plants, mainly from cool, mountainous regions in the Andes.

It was named after the Swedish baron Clas Alströmer (Claus von Alstroemer) by his close friend Carolus Linnaeus. The plant was first described by the French botanist Louis Feuillée. The plant's seeds were among many collected by Alströmer on a trip to South America in 1753.

The plants are tuberous or rhizomatous perennials. The young plant starts growing from the main rhizome. Another 5 to 7 rhizomes start growing from the main rhizome, sending up, per year, between 60 to 80 flowering stems. They grow to a height of 50-130 cm.

Each erect stem grows foliage of a few lanceolate leaves, and ends in an umbel of 3-10 flowers. These have 6 petals with spots, striped markings and contrasting patches.

The flower, which resembles a miniature lily, is very popular for bouquets and flower arrangements in the commercial cut flower trade. They have a vase life of about two weeks. It is sometimes called 'Ulster Mary' (as a word corruption).