While his genus monographs largely concentrated on Mediterranean flora, notably Epimedium,[82] Allium[92][93] and Paeonia,[94] he was also the author of species articles both popular and technical as well as a number of classical treatises.[18] In addition he produced floristic treatments of a number of regions such as Jamaica[95] and Nepal.[41] He also contributed to many national Florae as diverse as Bhutan[96] and Greece,[50] as well as major regional florae including the Flora Europaea[97] and European Garden Flora.[98]