Tuberose

Description

Agave amica, formerly Polianthes tuberosa, the tuberose, is a perennial plant in the family Asparagaceae, subfamily Agavoideae, extracts of which are used as a note in perfumery. Now widely grown as an ornamental plant, the species was originally native to Mexico. The common name derives from the Latin tuberosa through French tubéreuse, meaning swollen or tuberous in reference to its root system. The tuberose is herbaceous, growing from underground tubers or tuberous roots. It produces offsets. The leaves are a dull green and about 1–1.5 ft (30–50 cm) long and up to 0.5 in (13 mm) wide at the base. They are slightly succulent. The inflorescence is a spike, reaching up to 3 ft (1 m) high, with pure white waxy flowers. The flowers are tubular, with a tube up to 2.5 in (6 cm) long, separating into six flaring segments (tepals) at the end, and are strongly fragrant. There are six stamens, inserted into the tube of the flower, and a three-part stigma. The double-flowered cultivar 'The Pearl' has broader and darker leaves, and shorter flower spikes, usually reaching only 1.5–2 ft (50–60 cm). Orange-flowered forms of the species have been reported. The species was first described for science by Carl Linnaeus in 1753, as Polianthes tuberosa. In 1790, Friedrich Kasimir Medikus moved the species to the genus Tuberosa as Tuberosa amica. Both morphological and molecular phylogenetic studies have shown that Polianthes is embedded within the larger genus Agave, and the genus is now included in a broadly circumscribed Agave. Two incorrect attempts were made to name the species when transferred to Agave. In 1999, Joachim Thiede and Urs Eggli published the name "Agave tuberosa". However, Philip Miller had published this name in 1768, for the species now called Furcraea tuberosa, so it cannot be used again, and Thiede and Eggli's name is illegitimate. In 2001, Thiede and Eggli published a replacement name (nomen novum), "Agave polianthes". However, since Medikus's Tuberosa amica is considered to be a synonym of Polianthes tuberosa, its epithet is the second oldest and according to the International Code of Nomenclature for algae, fungi, and plants should be used when the older epithet is unavailable. Hence Thiede and Eggli's second name is superfluous, and the correct name for the species within Agave is Agave amica, as was explained by Thiede and Rafaël Govaerts when they published this combination in 2017.