Replace — Select all organisms with this family (replaces any current selection).

+ Add — Add matching organisms to the current selection. Use this to build a group with any of several families (OR).

∩ Filter — Narrow the current selection to only those organisms that also have this family (AND). Search for family A first, then filter down with family B to find organisms with both.

* To search for a second family without losing your current selection, clear the search box by backspacing or triple-clicking the text — do not use the × button, which resets everything.