The rank above the family
An order is the rank above the family. Where a family gathers plants that share the working details of a flower, an order gathers whole families that share a deeper ancestry, and the grouping is old enough that its members can look nothing like one another. Salvia, lilac, snapdragons and buddleia are all Lamiales, and what they have in common is a flower built with an upper and a lower lip rather than a ring of matching petals.
These 24 orders cover the 48 families in this guide. 12 of them hold exactly one family here, which is why none has a page to itself: an order page carrying a single family would say what the family page already says and compete with it for the same search. What an order genuinely does is group, so it is indexed rather than written up, and every card leads to the families inside it.
The pictures are doing real work. Each one shows relatives from the wider order rather than the flowers on the family page beneath it, because that is what the rank means. Rosales is apple and hawthorn blossom with hop cones, all of them cousins of the rose. Solanales is potato and tomato flowers, cousins of the morning glory. Proteales puts the sacred lotus beside a banksia cone, which is the pairing most people find hardest to believe.