Manihot grahamii: a new alien plant species in Europe
Manihot (Euphorbiaceae) is a genus of some 75-100 species which are native to North and South America. Species within the genus have been recorded as alien in North America, Asia, Africa and Australia. In 2014 Manihot esculenta was recorded for the first time as a casual alien in Europe where a population of 22 specimens was found in natural woodland in the Campania region in Southern Italy. Although M. esculenta is extensively cultivated as a crop in tropical and subtropical regions of the world, it is thought that the species is rarely grown as a garden ornamental in Europe. In 2015, the second record for this genus in Europe was reported where Manihot grahamii was identified in wasteland habitat (growing in clay substrate along ditches) in the Lazio region of Central Italy. M. grahamii was intentionally introduced into Italy as a garden ornamental in the 1970s. The current naturalized population consists of an established stand of 34 individuals of different ages which has been present for approximately ten years. Iberite & Iamonico (2015) note that further investigations are needed to verify the potential invasiveness of M. grahamii in Italy and other European regions.
Sources
Iberite M, Iamonico D (2015) Manihot grahamii Hook. (Euphorbiaceae), a new alien species for the Eurasian area with nomenclatural, taxonomical, morphological and ecological notes. Acta Botanica Croatica 74, 143-150.
Stinca A, D’Auria & Motti R (2014) Manihot esculenta (Euphorbiaceae) a new alien species in Italy Hacquetia 13, 335-357.