Early works describe
Durio sensu lato, which had 30 recognised species, with
Durio sensu stricto comprising 24 of them. The 6 additional species included in
Durio s.l. are now considered by some to comprise their own genus,
Boschia.
Durio s.s. and
Boschia have indistinguishable vegetative characteristics and many shared floral characteristics. The crucial difference between the two is that anther
locules open by apical pores in
Boschia and by longitudinal slits in
Durio s.s. These two genera form a
clade that is sister to another genus,
Cullenia. These three genera together form a clade that is characterised by highly modified (mono- and polythecate, as opposed to bithecate) anthers. this is now recognised as the
tribe Durioneae.
Durio was included in Bombacaceae because of the presence of monothecate anthers, as opposed to the bithecate anthers common to the rest of the mallows (and
angiosperms, in general). However, the first studies to examine mallow
phylogeny using molecular data found that the tribe Durioneae should be placed in the
subfamily Helicteroideae of an expanded Malvaceae. The authors of these studies hypothesise that monothecate anthers have most likely evolved convergently in Durioneae and in the Malvatheca clade (comprising Malvaceae s.l. subfamilies
Malvoideae and
Bombacoideae). == Description ==