Literature: Baillon (1874), Radcliffe-Smith (2001).
Phyllanthoid Euphorbiaceae are currently excluded from Euphorbiaceae, following recent molecular phylogenetic research (APGIII 2009). They are accommodated in a family of their own (Phyllanthaceae). Phylogenetic research furthermore supports the inclusion of Chamaesyce Gray (and Poinsettia J. Graham) in a broadly circumscribed genus Euphorbia (Zimmermann & al. 2010).
An overview of current research on Euphorbiaceae is available here: http://www.euphorbiaceae.org.
1 Leaves alternate, palmately lobed. Milky latex absent === 2
Leaves opposite or alternate, entire or serrate but never lobed. Milky latex present or absent === 3
2 Milky latex absent. Glands subtending each inflorescence bract 2. Stamens very numerous, up to 1000 === Ricinus
Milky latex present. Glands subtending each inflorescence bract absent. Stamens 10 === Manihot
3 Capsule 2-loculate. Milky latex absent. Leaves opposite. Plant usually dioecious (native) === Mercurialis
Capsule 3-loculate. Milky latex present. Leaves alternate or opposite. Plant monoecious === Euphorbia (incl. Chamaesyce and Poinsettia)
Additional aliens: Three species of Acalypha L. have recently been recorded as greenhouse weeds and/or as ephemeral introductions associated with container plants (Verloove 2006, Hoste & al. 2009): A. australis L., A. indica L. and A. virginica L. Thus far, none of these species was seen “in the wild” in Belgium but their occurrence in a near future is not unlikely.
APG III (2009) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. APG III. Bot. J. Linn. Soc. 161(2): 105-121.
Baillon H.E. (1874) Monographie des Euphorbiacées. V. Masson, Paris.
Hoste I., Verloove F., Nagels C., Andriessen L. & Lambinon J. (2009) De adventievenflora van in België ingevoerde mediterrane containerplanten. Dumortiera 97: 1-16. [available online at: http://www.br.fgov.be/DUMORTIERA/DUM_97/Dum%2097_1-16_Mediterrane%20cont...
Radcliffe-Smith A. (2001) Genera Euphorbiacearum. Royal Botanic Gardens, Kew: X + 455 p.
Verloove F. (2006) Catalogue of neophytes in Belgium (1800-2005). Scripta Botanica Belgica 39: 89 p.
Zimmermann N.F.A., Ritz C.M. & Hellwig F.H. (2010) Further support for the phylogenetic relationships within Euphorbia L. (Euphorbiaceae) from nrITS and trnL-trnF IGS sequence data. Plant Syst. Evol. 286: 39-58.