Rhamnaceae and Smilacaceae

Rhamnus cathartica vs Smilax tamnoides

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

Rhamnus cathartica, photographed by Jason Grant
fig. a Jason Grant, CC BY 4.0

Rhamnus cathartica

common buckthorn
Smilax tamnoides, photographed by Sarah Culliton
fig. b Sarah Culliton, CC BY 4.0

Smilax tamnoides

bristly greenbrier

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Smilax tamnoides Rhamnus cathartica 3 of 20 (15%)

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

What actually separates themon the record

Family Rhamnaceae versus Smilacaceae. Different families, which is a real separation.
Genus Rhamnus versus Smilax.
Flowering Peaks in May versus April. If the plant is in flower, timing helps. (n = 420 and 62.)

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