Definitions
1.nounCrataegus monogyna, a hawthorn species native to Europe, northwest Africa and western Asia.
2.nounBursaria spinosa, a small Australian shrub.
3.nounVachellia constricta, formerly Acacia constricta, whitethorn acacia, a shrub in the family Fabaceae.
4.nounCeanothus leucodermis, chaparral whitethorn, a shrub in the family Rhamnaceae.