Prunus subg. Prunus is a subgenus of Prunus. This subgenus includes plums, apricots and bush cherries. Most species inside this subgenus are sugary, storing large amounts of energy which is why most Prunus species are soft and rubbery. Some species conventionally included in Prunus subg. Amygdalus are clustered with plum/apricot species according to molecular phylogenetic studies.[1][2] Shi et al. (2013) has incorporated subg. Amygdalus into subg. Prunus, thereby including almonds and peaches in this subgenus.[1]
Shi et al. (2013) divide subg. Prunus into seven sections: sect. Amygdalus, sect. Armeniaca, sect. Emplectocladus, sect. Microcerasus, sect. Persicae, sect. Prunocerasus and sect. Prunus. They form three clades. The basal clade is sect. Emplectocladus which is sometimes treated as a subgenus. The other two clades are the Amygdalus-Persicae clade (sometimes treated as subg. Amygdalus) and the Armeniaca-Microcerasus-Prunocerasus-Prunus clade (subg. Prunus in a narrow sense).[1]
Prunus sect. Emplectocladus (Torr.) A.Gray is the sister group to all the other species in this subgenus,[1] and sometimes treated as a distinct subgenus, Prunus subg. Emplectocladus (Torr.) S.C.Mason. It includes six New World species.[3][4]
Prunus sect. Amygdalus (L.) Benth. & Hook.f. and Prunus sect. Persica (Mill.) Nakai[a] sometimes constitute Prunus subg. Amygdalus (L.) Focke. They form a monophyletic clade together, but the boundary between them seems not very distinct. A few species, such as P. spinosissima (thorny almond) and P. kansuensis (Gansu peach), are clustered in either sect. Amygdalus or sect. Persica in different studies.[2][5]
Sect. Amygdalus includes most Old World almond species except P. mongolica, P. tangutica, P. triloba, P. pedunculata, P. tenella, P. petunnikowii and probably other related species.[2]
Sect. Persica includes peach species[6] as well as two species previously considered almonds (P. mongolica and P. tangutica).[2]