Both Cactaceae
Echinocactus horizonthalonius vs Lophophora williamsii
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, 3 times. We publish the rate, and then we tell you what actually separates them.
Confused 3x by our model Method published
Side by sidefigs. a and b
Echinocactus horizonthalonius
Devilshead
Lophophora williamsii
Peyote
How often our model gets it wrong measured, not estimated
| When the plant was | The model said | How often |
|---|---|---|
| Lophophora williamsii | Echinocactus horizonthalonius | 3 of 20 (15%) |
Measured on 38,299 openly licensed, research-grade photographs. Full method and dataset.
What actually separates themon the record
| Family | Both Cactaceae. The family does not separate them. |
|---|---|
| Genus | Echinocactus versus Lophophora. |
| Flowering | Peaks in May versus March. If the plant is in flower, timing helps. (n = 514 and 130.) |
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.