Alnus glutinosa vs Alnus rubra
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.
Side by sidefigs. a and b
Alnus glutinosa
Alnus rubra
How often our model gets it wrong measured, not estimated
| When the plant was | The model said | How often |
|---|---|---|
| Alnus glutinosa | Alnus rubra | 3 of 20 (15%) |
The confusion runs one way only. The model mistakes Alnus glutinosa for Alnus rubra, 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 Betulaceae. The family does not separate them. |
|---|---|
| Genus | Both Alnus. Congeners, which is why this is hard. |
| Flowering | Peaks in March versus March. Timing does not separate them. (n = 489 and 155.) |
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.