Laportea aestuans (L.) Chew (syn.: Urtica aestuans L., Fleurya aestuans (L.) Gaudich. ex Miq.) (trop.) – A very rare and probably ephemeral alien. Sometimes seen as a weed in greenhouses and plant nurseries since 1999 (Verloove 2006), but only indoors. In 2016 a single individual was recorded at the foot of a wall in Brussels.
Selected literature:
Hsu T.-W., Chiang T.-Y. & Chung N.-J. (2003) Laportea aestuans (L.) Chew (Urticaceae), a newly recorded plant in Taiwan. Taiwania 48(1): 72-76. [available online at: http://tai2.ntu.edu.tw/taiwania/pdf/tai.2003.48.72.pdf]
Verloove F. (2006) Catalogue of neophytes in Belgium (1800-2005). Scripta Botanica Belgica 39: 89 p. [available online at: http://alienplantsbelgium.be/sites/alienplantsbelgium.be/files/tabel_2.pdf]