Both Sorbus

Sorbus americana vs Sorbus aucuparia

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

Confused 5x by our model Same genus Sorbus Method published

Side by sidefigs. a and b

Sorbus americana, photographed by Ashwin Srinivasan
fig. a Ashwin Srinivasan, CC BY 4.0

Sorbus americana

American mountain ash
Sorbus aucuparia, photographed by Alexis Tinker-Tsavalas
fig. b Alexis Tinker-Tsavalas, CC BY 4.0

Sorbus aucuparia

European mountain ash

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Sorbus americana Sorbus aucuparia 3 of 18 (17%)
Sorbus aucuparia Sorbus americana 2 of 18 (11%)

The confusion is asymmetric, which is common and usually informative: it means one of these has a character the other lacks, rather than the two simply looking alike.

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

What actually separates themon the record

Family Both Rosaceae. The family does not separate them.
Genus Both Sorbus. Congeners, which is why this is hard.
Flowering Peaks in June versus May. If the plant is in flower, timing helps. (n = 185 and 1,728.)

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