Both Spiranthes
Spiranthes cernua vs Spiranthes romanzoffiana
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.
Side by sidefigs. a and b
Spiranthes cernua
nodding ladies' tresses
Spiranthes romanzoffiana
Hooded Ladies' Tresses
How often our model gets it wrong measured, not estimated
| When the plant was | The model said | How often |
|---|---|---|
| Spiranthes romanzoffiana | Spiranthes cernua | 3 of 17 (18%) |
Measured on 38,299 openly licensed, research-grade photographs. Full method and dataset.
What actually separates themon the record
| Family | Both Orchidaceae. The family does not separate them. |
|---|---|
| Genus | Both Spiranthes. Congeners, which is why this is hard. |
| Flowering | Peaks in October versus August. If the plant is in flower, timing helps. (n = 429 and 736.) |
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.