the genus ilex is widespread throughout the temperate and subtropical regions of the world it includes species of trees shrubs and climbers with evergreen or deciduous foliage and inconspicuous flowers its range was more extended in the tertiary period and many species are adapted to laurel forest habitat it occurs from sea level to more than  metres  ft with high mountain species it is a genus of small evergreen trees with smooth glabrous or pubescent branchlets the plants are generally slow-growing with some species growing to  m  ft tall the type species is the european holly ilex aquifolium described by linnaeus