Andesanthus is a genus of flowering plant in the family Melastomataceae, native to Colombia, Costa Rica, Ecuador, Panama, Peru and Venezuela. The genus was established in 2019 for some species formerly placed in Tibouchina. Some species are cultivated as ornamental shrubs or trees.
Description
Species of Andesanthus are trees between 5 and 20 m tall at maturity or shrubs 1–3 m tall. Their leaves are opposite and petiolate (stalked). The inflorescence is a terminal panicle or some modification of a panicle. The flowers are perigynous with a bell- or urn-shaped hypanthium, externally covered with many soft hairs (pubescent) in most species. The flowers have five free petals, which are pink, purple, magenta or white in colour, or initially magenta or rose-red fading to lavender with age. Flowers have ten stamens, either all the same size or in two distinct sizes. The connective at the base of the anther of the stamen is prolonged and modified into a bilobed ventral appendage. The numerous seeds are shaped like a spiral (cochleate) which may be elongated.
Andesanthus can be distinguished by its coating of small flattened scales (lepidote), hairless (glabrous) stamens which either have all their anthers yellow if of one size or have the larger anthers yellow and the smaller anthers pink or red if of two sizes.
Taxonomy
The genus Andesanthus was erected in 2019. The name reflects the fact that the majority of species occur in the Andes.
In 1885, in his treatment for Flora brasiliensis, Alfred Cogniaux used a broad concept of the genus Tibouchina, transferring into it species at that time placed in many other genera. This broad concept was generally adopted subsequently, and around 470 taxa were at one time or another assigned to Tibouchina, including those placed in Andesanthus in 2019. A phylogenetic analysis in 2013 based on molecular data (2 plastid and 1 nuclear regions) showed that the traditional circumscription of Tibouchina was paraphyletic. Four...
