Description from Flora of China
Oleaster Heister ex Fabricius.
Shrubs, sometimes climbing, or small trees, deciduous or evergreen, sometimes spiny. Leaves alternate, petiolate, blade margin usually entire. Flowers bisexual, clustered on short axillary shoots, sometimes solitary. Calyx tubular, 4-lobed, constricted above ovary and breaking at constriction as fruit develops; lobes usually spreading, deciduous, white or yellow inside. Stamens 4, inserted in mouth of calyx tube, alternate with lobes. Style linear, not exserted. Drupe globose or ellipsoid, rarely longitudinally winged (E. mollis); stone usually 8-ribbed, with a large straight embryo.
Many taxa are separated only by quantitative characters, and better information on population variation is likely to lead to a significant reduction in the number of species recognized. Indeed, recent studies (Du, Fl. Yunnan. 12: 749-776. 2006) suggest that some species of Elaeagnus should be combined.
Species no. 35, Elaeagnus xingwenensis, was described from fruiting material and could not be included in this key. There is an unsubstantiated record of E. murakamiana Makino from China and Korea, but current Japanese floras treat this species as endemic to Japan, so it seems best to exclude it from this treatment.
After publication of the family treatment for the Flora of China, this genus was revised by Miao SUN and Qi LIN (J. Syst. Evol. 48(5): 356-390. 2010).
About 90 species: Asia, S Europe, North America; 67 species (55 endemic) in China.