[Wikipedia] Similar Species: Similar species include Veronica anagallis-aquatica (with purply-blue flowers), Veronica anagalloides (with elliptic fruits), Veronica × lackschewitzii (fruits fail to form, frequently very large plants) and also Veronica scardica and Veronica beccabunga. (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: 03/29/2025).