"Stewart Robert Hinsley" schreef
The Angiosperm Phylogeny Website has synapomorphies for all sorts of
suprafamilial clades - but as often as not some members of the clade have
secondarily lost the trait.

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Yes, the higher the rank of the taxon, the harder it is to give a
description that is true for all its members. Synapomorphies are lost by
some members, are not present in the basal members, or are expressed
differently in the basal members.

Environment often has a major influence on morphology as well. Putting
together an accurate description is not only a lot of work, but requires
skill and experience.
PvR