Both Euphorbia

Euphorbia bicolor vs Euphorbia marginata

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, 4 times. We publish the rate, and then we tell you what actually separates them.

Confused 4x by our model Same genus Euphorbia Method published

Side by sidefigs. a and b

Euphorbia bicolor, photographed by Chris Hughes
fig. a Chris Hughes, CC BY 4.0

Euphorbia bicolor

snow-on-the-prairie
Euphorbia marginata, photographed by Meghan Cassidy
fig. b Meghan Cassidy, CC BY-SA 4.0

Euphorbia marginata

snow-on-the-mountain

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Euphorbia marginata Euphorbia bicolor 4 of 19 (21%)

Measured on 38,949 openly licensed, research-grade photographs. Full method and dataset.

What actually separates themon the record

Family Both Euphorbiaceae. The family does not separate them.
Genus Both Euphorbia. Congeners, which is why this is hard.
Flowering Peaks in September versus September. Timing does not separate them. (n = 161 and 404.)

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