Asystasia gangetica subsp. micrantha, a newly naturalized plant in Taiwan
Asystasia gangetica subsp. micrantha (Acanthaceae) was found naturalized in southern Taiwan. This taxon represents a new record for the genus and the species on the island. The genus includes approximately 70 species in the world, distributed in Africa, India, mainland China and Australia. This plant is a perennial herb, erect, 15 to 60 cm tall. The leaves are opposite, ovate, 4-9 cm long, 2-5 cm wide. The corolla is zygomorphic, about 1-1.3 cm in diameter, white, bell-shaped. Plant nodes form roots when they enter in contact with moist soil, ultimately forming mats or sprawling mass stems. Given such asexual propagation and lack of natural predators, these plants are highly invasive and are considered as weeds. The introduction of this weed has caused serious disturbance to natural habitats, particularly in Malaysia, Indonesia and the Pacific islands. For more information on this plant: http://www.hear.org/pier/species/asystasia_gangetica.htm
Sources
Hsu TW, Chiang TY, Peng JJ (2005) Asystasia gangetica (l.) T. Anderson subsp. micrantha (Nees) Ensermu (Acanthaceae), a newly naturalized plant in Taiwan. Taiwania, 50(2), 117-122.