Osmundaceae and Dennstaedtiaceae

Osmunda regalis vs Pteridium aquilinum

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 Method published

Side by sidefigs. a and b

Osmunda regalis, photographed by Rafael Medina
fig. a Rafael Medina, CC BY 4.0

Osmunda regalis

European royal fern
Pteridium aquilinum, photographed by Michael Warner
fig. b Michael Warner, CC BY 4.0

Pteridium aquilinum

common bracken

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Osmunda regalis Pteridium aquilinum 5 of 19 (26%)

The confusion runs one way only. The model mistakes Osmunda regalis for Pteridium aquilinum, but not the reverse.

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

What actually separates themon the record

Family Osmundaceae versus Dennstaedtiaceae. Different families, which is a real separation.
Genus Osmunda versus Pteridium.

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