Rosaceae and Rutaceae

Rosa multiflora vs Zanthoxylum americanum

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

Rosa multiflora, photographed by Liz Crafford
fig. a Liz Crafford, CC BY 4.0

Rosa multiflora

multiflora rose
Zanthoxylum americanum, photographed by Cazody
fig. b Cazody, CC0 1.0

Zanthoxylum americanum

northern prickly ash

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Zanthoxylum americanum Rosa multiflora 3 of 20 (15%)

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

What actually separates themon the record

Family Rosaceae versus Rutaceae. Different families, which is a real separation.
Genus Rosa versus Zanthoxylum.
Flowering Peaks in May versus May. Timing does not separate them. (n = 6,756 and 241.)

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