Flora mirabilis ("The Wondrous Flower") is an opera in three acts composed by Spyros Samaras to an Italian-language libretto by Ferdinando Fontana.

[1] A 20th-century description of Flora mirabilis in Gelli's Dizionario dell'Opera points out that despite having a Greek composer trained in France and a story set in medieval Sweden, the opera adhered quite strictly to the characteristic elements of late 19th-century Italian opera—folkloric dances, large choruses, and lengthy orchestral passages used to set both the geographical and the psychological atmosphere.

George Leotsakos and other authors have compared the musical idiom and proto-verismo displayed in Flora to that of Puccini whose first two operas, Le Villi and Edgar, also had libretti by Fontana.

[5] The premiere of Flora mirabilis at the Teatro Carcano in May 1886 proved to be a great success with both the composer and the librettist brought to the stage for multiple curtain calls.

[7] The full score to Flora mirabilis was lost in 1943 when Samaras's publisher Casa Sonzogno was hit during the Allied bombing of Milan.