Phrymaceae and Primulaceae

Erythranthe cardinalis vs Lysimachia arvensis

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 Method published

Side by sidefigs. a and b

Erythranthe cardinalis, photographed by George Williams
fig. a George Williams, CC BY 4.0

Erythranthe cardinalis

scarlet monkeyflower
Lysimachia arvensis, photographed by Zeke Marshall
fig. b Zeke Marshall, CC BY 4.0

Lysimachia arvensis

scarlet pimpernel

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Erythranthe cardinalis Lysimachia arvensis 3 of 20 (15%)

The confusion runs one way only. The model mistakes Erythranthe cardinalis for Lysimachia arvensis, but not the reverse.

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

What actually separates themon the record

Family Phrymaceae versus Primulaceae. Different families, which is a real separation.
Genus Erythranthe versus Lysimachia.
Flowering Peaks in July versus April. If the plant is in flower, timing helps. (n = 2,167 and 12,305.)

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