Ismene, or Peruvian daffodil, is a genus of South American plants in the Amaryllis family. The species are native to Peru and Ecuador and widely cultivated elsewhere as ornamentals because of their large, showy flowers.
Ismene produces tender perennial bulbs bearing a strong resemblance to those of Hymenocallis, a genus into which Ismene had often been grouped in the past. However, its morphology differs from Hymenocallis in several significant ways: its vegetative parts, natural range, and chromosome number are all distinct.
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Taxonomy
The genus Ismene Salisb. ex Herb. was validly described in 1821 by William Herbert with Ismene amancaes (Ruiz & Pav.) Herb. as the type species based on previous work by Richard Anthony Salisbury.
Species
A list of Ismene species and their geographic distribution is given below.
Ismene amancaes (Ruiz & Pav.) Herb – western Peru
Ismene hawkesii (Vargas) Gereau & Meerow – Cusco, Peru
Ismene longipetala (Lindl.) Meerow – southwestern Ecuador, northwestern Peru
Ismene morrisonii (Vargas) Gereau & Meerow – Apurímac, Peru
Ismene narcissiflora (Jacq.) M.Roem. – south-central Peru
Ismene nutans (Ker Gawl.) Herb. – Peru
Ismene pedunculata Herb. – Peru
Ismene ringens (Ruiz & Pav.) Gereau & Meerow – Peru
Ismene sublimis (Herb.) Gereau & Meerow – La Libertad, Peru
Ismene vargasii (Velarde) Gereau & Meerow – Peru
Hybrids
Ismene × deflexa Herb. (I. longipetala × I. narcissiflora) – Peru
Phylogeny
It is closely related to Leptochiton and Hymenocallis, from which it separated 26.14 million years ago. The separation of Leptochiton and Hymenocallis occurred 24.46 million years ago.