Cystopteris bulbifera vs Cystopteris fragilis
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.
Side by sidefigs. a and b
Cystopteris bulbifera
Cystopteris fragilis
How often our model gets it wrong measured, not estimated
| When the plant was | The model said | How often |
|---|---|---|
| Cystopteris bulbifera | Cystopteris fragilis | 3 of 20 (15%) |
| Cystopteris fragilis | Cystopteris bulbifera | 2 of 20 (10%) |
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 Cystopteridaceae. The family does not separate them. |
|---|---|
| Genus | Both Cystopteris. Congeners, which is why this is hard. |
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.