That Takhtajan and I retain the two orders in 1997 while Thorne, and later Bremer et al. This is a matter of taxonomic judgement. Much more important, however, is the recent tendency to remove the Oleaceae away from the Gentianales although not all of the recent data supports the trend. At the moment, all of us are following the molecular data of the 1990s instead of some of the chemical data generated in the 1980s. Arn., with Thorne including the Nyctanthoideae in the former.
Petals are always present in the former but occasionally lacking in some species of the latter.
He distinguishes the monogeneric Nyctanthoideae on the basis of the flowers having 5-8 petals and an ovary with a single ovule in each locule. The Oleoideae is divisible into the Fraxineae Bartl. Many taxa of the family are economically important. Numerous species are cultivated as ornamentals, with Forsythia , Jasminum , Ligustrum , and Syringa commonly encountered in temperate regions. The genus Chionanthus , often called the fringe-tree, is one of the more lovely trees to flower in the spring and early summer.