Evolutionary considerations of the presence of both morphophysiological and physiological seed dormancy in the highly advanced euasterids II order Dipsacales

Although the underdeveloped embryo, and thus
morphological (MD) or morphophysiological (MPD)
seed dormancy, is basal in angiosperms, it also
occurs in advanced groups. A synthesis of the
literature, combining phylogeny and the kind of seed
dormancy in the highly evolutionarily advanced order
Dipsacales, shows that MPD (or MD) occurs throughout
all clades except the most advanced one, Valerina.
Seeds of taxa in the Valerina clade have fully
developed embryos and physiological dormancy
(PD) or are non-dormant (ND); thus, PD and ND are
derived conditions in Dipsacales. Assuming that types
of seed dormancy have not changed since the Early
Tertiary, the fossil record suggests that MPD (or MD)
was present in extant genera of Dipsacales by the
Palaeocene, but PD (or ND) not until the Miocene.
Molecular dating indicates that the ages of dipsacalean
lineages with MPD and PD are older than those
indicated by the fossil evidence.