Both Rubus

Rubus occidentalis vs Rubus ursinus

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 Rubus Method published

Side by sidefigs. a and b

Rubus occidentalis, photographed by Ryan Sorrells
fig. a Ryan Sorrells, CC BY 4.0

Rubus occidentalis

black raspberry
Rubus ursinus, photographed by Casey H. Richart
fig. b Casey H. Richart, CC BY 4.0

Rubus ursinus

trailing blackberry

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Rubus occidentalis Rubus ursinus 3 of 20 (15%)

The confusion runs one way only. The model mistakes Rubus occidentalis for Rubus ursinus, but not the reverse.

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

What actually separates themon the record

Family Both Rosaceae. The family does not separate them.
Genus Both Rubus. Congeners, which is why this is hard.
Flowering Peaks in May versus April. If the plant is in flower, timing helps. (n = 347 and 3,099.)

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