Alismataceae and Plantaginaceae

Alisma subcordatum vs Plantago major

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 Method published

Side by sidefigs. a and b

Alisma subcordatum, photographed by Bonnie Semmling
fig. a Bonnie Semmling, CC BY 4.0

Alisma subcordatum

american water-plantain
Plantago major, photographed by Randy A Nonenmacher
fig. b Randy A Nonenmacher, CC BY 4.0

Plantago major

greater plantain

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Alisma subcordatum Plantago major 4 of 19 (21%)

The confusion runs one way only. The model mistakes Alisma subcordatum for Plantago major, but not the reverse.

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

What actually separates themon the record

Family Alismataceae versus Plantaginaceae. Different families, which is a real separation.
Genus Alisma versus Plantago.
Flowering Peaks in July versus July. Timing does not separate them. (n = 214 and 1,826.)

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