Compositae Working Group (CWG) (2025). Global Compositae Database. Machaeranthera attenuata Howell. Accessed at: https://compositae.org/gcd/aphia.php?p=taxdetails&id=1171581 on 2025-09-12
original description(1901). Fl. N.W. Amer. 1 page(s): 314 [details]
Unreviewed
Contributed data: Published Data only shown for fields conflicting with the consensus taxon record A Flora of Northwest America 3: [Tropicos] [details] LSID urn:lsid:compositae.org:names:982A3965-1800-489A-81A5-20D49EE50349 [details] Type material s.n., Howell, lectotype ORE [details]