Dichondra micrantha  

Dichondra micrantha Urb. (syn.: D. repens auct.) (E As.) – A very rare and ephemeral alien. Scattered individuals were found in 2017 on dredging sludge from river Scheldt in Bilzen-Genk. The exact origin of these plants remains obscure. They grew together with many other noteworthy aliens such as Desmanthus spec., Ipomoea coccinea, Malvastrum coromandelianum, Pelargonium candicans, Senna obtusifolia, etc. At least some of these are probably associated with soy bean importation. See also: http://alienplantsbelgium.be/content/extraordinary-collection-alien-plan....
Dichondra micrantha is now found in many warm-temperate and subtropical regions of the world. It was originally introduced as a substitute for grasses in lawns (also as ground cover or soil binder) but readily escaped and now has become weedy in several countries, also in southern Europe. Further north it is an exceptional and usually ephemeral alien. It was established for some time in coastal dunes in Cornwall in the British Isles (Stace 2010). 
This species was long known as (and is still sometimes confused with; see Zielinski & Tan 2000) D. repens. The latter, however, is a species confined to Australia and New Zealand (Lawalrée 1970, Forde 1978).

Selected literature

Austin D.F. (1998) The indiscriminate vector: Human distribution of Dichondra micrantha (Convolvulaceae). Economic Botany 52: 88-106.

Falcao W.F. de A. & Falcao J.I. de A. (1982) Contribuicao ao estudo das Convolvulaceae, do Espirito Santo. Rodriguesia 33(56): 101-116.

Forde M.B. (1978) The cultivated Dichondra. New Zealand J. Bot. 16(2): 283-285.

Lawalrée A. (1970) Définition, aire et mode de dissémination de Dichondra micrantha Urban (Convolvulaceae). Acta Bot. Neerl. 19: 717-721.

Manitz H. (1978) Zur verbreitung von Dichondra micrantha Urb. (Convolvulaceae) in Cuba. Wissenschaft. Zeitschr. Friedrich-Schiller-Univ., Math.-Naturwiss. 27(1): 27-32.

Mattos J.R. (1976) Novidades taxonomicas em plantas do Brasil: 2. Loefgrenia 70: 3-6.

Russell J. (1956) Dichondra repens. Bot. Soc. Brit. Isles Proc. 2: 21-22. 

Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.

Welman W.G. (1999) Convolvulaceae: notes on Dichondra and Xenostegia in southern Africa. Bothalia 29(2): 253-254. [available online at: https://abcjournal.org/index.php/ABC/article/viewFile/596/540]

Zielinski J. & Tan K. (2000) Dichondra repens (Convolvulaceae), a new alien species in the flora of Turkey. Karaca Arbor.Mag. 5(3): 119-124.