Both Adiantum

Adiantum capillus-veneris vs Adiantum jordanii

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.

Confused 3x by our model Same genus Adiantum Method published

Side by sidefigs. a and b

Adiantum capillus-veneris, photographed by Daniel Cahen
fig. a Daniel Cahen, CC BY 4.0

Adiantum capillus-veneris

black maidenhair fern
Adiantum jordanii, photographed by Michael Warner
fig. b Michael Warner, CC BY 4.0

Adiantum jordanii

California Maidenhair Fern

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Adiantum jordanii Adiantum capillus-veneris 3 of 20 (15%)

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

What actually separates themon the record

Family Both Pteridaceae. The family does not separate them.
Genus Both Adiantum. 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.

Both recordsfull pages