Both Castanea

Castanea dentata vs Castanea sativa

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

Confused 4x by our model Same genus Castanea Method published

Side by sidefigs. a and b

Castanea dentata, photographed by Michael J. Papay
fig. a Michael J. Papay, CC BY 4.0

Castanea dentata

American chestnut
Castanea sativa, photographed by Patrick Meurin
fig. b Patrick Meurin, CC BY 4.0

Castanea sativa

Sweet Chestnut

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Castanea sativa Castanea dentata 4 of 20 (20%)

Measured on 38,949 openly licensed, research-grade photographs. Full method and dataset.

What actually separates themon the record

Family Both Fagaceae. The family does not separate them.
Genus Both Castanea. Congeners, which is why this is hard.
Flowering Peaks in July versus June. If the plant is in flower, timing helps. (n = 153 and 179.)

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