The tree is packed with empty circles.

Mara has thirty-three minutes to move the travelling display downstairs. The courier is early; the curator is stuck across town; rain has begun tapping the high archive windows.
Across the long table, a branching map holds twelve blank circles. Beside it wait three open cases: fossil casts, a comparison of wings, and a pouch of thin brass rings.
Dr Vale’s note contains one sentence: If the evidence cannot travel with the line, leave the circle blank.