[Wikipedia] Similarity to Taraxacum officinale: Agoseris monticola resembles the common dandelion (Taraxacum officinale) in having no leafy stems, only a rosette of leaves close to the ground. There is a single flower head with many yellow ray florets but no disc florets. (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: 03/31/2025).
