Both Populus

Populus deltoides vs Populus fremontii

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 Populus Method published

Side by sidefigs. a and b

Populus deltoides, photographed by Jack Forrester
fig. a Jack Forrester, CC BY 4.0

Populus deltoides

Eastern Cottonwood
Populus fremontii, photographed by Alan Rockefeller
fig. b Alan Rockefeller, CC BY 4.0

Populus fremontii

Frémont Cottonwood

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Populus fremontii Populus deltoides 4 of 19 (21%)

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

What actually separates themon the record

Family Both Salicaceae. The family does not separate them.
Genus Both Populus. Congeners, which is why this is hard.
Flowering Peaks in April versus March. If the plant is in flower, timing helps. (n = 379 and 166.)

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