Every accepted species in the genus is listed. A name links to its page when we hold at least three commercially licensed photographs of it. Where we do not, the row shows how many we actually found, which is usually none.
| Species | Authority | Usable photographs | Page |
|---|---|---|---|
| Corylus avellana | L. | 4,135 | documented |
| Corylus cornuta | Marshall | 1,609 | documented |
| Corylus americana | Walter | 881 | documented |
| Corylus colurna | L. | 35 | documented |
| Corylus heterophylla | Fisch. ex Trautv. | 24 | documented |
| Corylus sieboldiana | Blume | 7 | documented |
| Corylus ferox | Wall. | 2 | below the evidence gate |
| Corylus jacquemontii | Decne. | 1 | below the evidence gate |
| Corylus × colurnoides | C.K.Schneid. | 0 | below the evidence gate |
| Corylus chinensis | Franch. | 0 | below the evidence gate |
| Corylus colchica | Albov | 0 | below the evidence gate |
| Corylus fargesii | (Franch.) C.K.Schneid. | 0 | below the evidence gate |
| Corylus maxima | Mill. | 0 | below the evidence gate |
| Corylus potaninii | Bobrov | 0 | below the evidence gate |
| Corylus wangii | Hu | 0 | below the evidence gate |
| Corylus wulingensis | Q.X.Liu & C.M.Zhang | 0 | below the evidence gate |
| Corylus yunnanensis | (Franch.) A.Camus | 0 | below the evidence gate |
This site is commercial, so it can only publish photographs licensed for commercial use. Roughly three quarters of the photographs on iNaturalist are CC BY-NC, which excludes them. A species needs at least three usable photographs before we will build it a page, because a page with one picture and no traits tells you nothing you could not get from a search result, and generating hundreds of thousands of those is precisely the practice that got the previous version of this site deleted.
So the species above without a link are not errors and they are not omissions. They are real, accepted plants that we cannot yet document to the standard we hold ourselves to, and the count in the photographs column is exactly how far short we fall.