Distribution map of Buxus sempervirens (European box).
     Native continuous range
✖ Native isolated population
Caudullo, G., Welk, E., San-Miguel-Ayanz, J., 2017. Chorological maps for the main European woody species. Data in Brief 12, 662-666. DOI: 10.1016/j.dib.2017.05.007
Data: https://doi.org/10.6084/m9.figshare.11359538 
References:

Di Domenico, F., Lucchese, F., Magri, D., 2011. Late glacial and Holocene history of Buxus sempervirens L. in Italy. Annali di Botanica, 1: 45-58. DOI: 10.4462/annbotrm-9123
Di Domenico, F., Lucchese, F., Magri, D., 2012. Buxus in Europe: Late Quaternary dynamics and modern vulnerability. Perspectives in plant ecology, evolution and systematics, 14(5): 354-362. DOI: 10.1111/j.2006.0030-1299.14826.x
Essl, F., 2002. Verbreitung und Gesellschaftsanschluss des Buchsbaumes (Buxus sempervirens L.) im oberösterreichischen Enns- und Steyrtal. Verhandlungen der Zoologisch-Botanischen Gesellschaft in Österreich, 139: 75-95.
Giovanni Caudullo