[efloras.org] South America Native: Chenopodium macrospermum is native and diverse in South America. Much, if not all, of the North American material is introduced from there and appears to represent more than one part of the variation. (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: 04/03/2025).