Both Arctium

Arctium lappa vs Arctium minus

These two are not on this page because a keyword tool suggested them. They are here because our own identification model genuinely mistook one for the other, on real photographs, 6 times. We publish the rate, and then we tell you what actually separates them.

Confused 6x by our model Same genus Arctium Method published

Side by sidefigs. a and b

Arctium lappa, photographed by Jason Grant
fig. a Jason Grant, CC BY 4.0

Arctium lappa

greater burdock
Arctium minus, photographed by Stephen James McWilliam
fig. b Stephen James McWilliam, CC0 1.0

Arctium minus

lesser burdock

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Arctium lappa Arctium minus 6 of 20 (30%)

The confusion runs one way only. The model mistakes Arctium lappa for Arctium minus, but not the reverse.

Measured on 38,299 openly licensed, research-grade photographs. Full method and dataset.

What actually separates themon the record

Family Both Asteraceae. The family does not separate them.
Genus Both Arctium. Congeners, which is why this is hard.
Flowering Peaks in July versus August. If the plant is in flower, timing helps. (n = 1,017 and 1,575.)

What we do not have yet: the diagnostic morphological character that a botanist would key on, from a source we can cite. We are not going to invent one. Until we have it, this page tells you the two are genuinely confusable, how often, and what the taxonomy and the flowering data do and do not settle.

Both recordsfull pages