[Wikipedia] Flower Size: Wolffia globosa has been described as the world's smallest flowering plant, at 0.1 - 0.2 mm (0.004 - 0.008 in) in diameter.[4][5] (link added by Mary Ann Machi)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2025.The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 04/02/2025).