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 |
|---|---|---|---|
| Ferocactus wislizeni | (Engelm.) Britton & Rose | 5,350 | documented |
| Ferocactus acanthodes | (Lem.) Britton & Rose | 4,266 | documented |
| Ferocactus histrix | (DC.) G.E.Linds. | 240 | documented |
| Ferocactus townsendianus | Britton & Rose | 214 | documented |
| Ferocactus viridescens | (Torr. & A.Gray) Britton & Rose | 140 | documented |
| Ferocactus piliferus | (Lem.) G.Unger | 136 | documented |
| Ferocactus latispinus | (Haw.) Britton & Rose | 123 | documented |
| Ferocactus emoryi | (Engelm.) Orcutt | 74 | documented |
| Ferocactus uncinatus | (Galeotti ex Pfeiff.) Britton & Rose | 71 | documented |
| Ferocactus echidne | (DC.) Britton & Rose | 46 | documented |
| Ferocactus hamatacanthus | (Muehlenpf.) Britton & Rose | 37 | documented |
| Ferocactus herrerae | J.G.Ortega | 32 | documented |
| Ferocactus mathssonii | (Berge ex K.Schum.) N.P.Taylor | 27 | documented |
| Ferocactus peninsulae | (F.A.C.Weber) Britton & Rose | 26 | documented |
| Ferocactus glaucescens | (DC.) Britton & Rose | 18 | documented |
| Ferocactus gracilis | H.E.Gates | 18 | documented |
| Ferocactus robustus | (Link & Otto) Britton & Rose | 18 | documented |
| Ferocactus haematacanthus | (Salm-Dyck) Bravo ex Backeb. & F.M.Knuth | 15 | documented |
| Ferocactus macrodiscus | (Mart.) Britton & Rose | 15 | documented |
| Ferocactus diguetii | (F.A.C.Weber) Britton & Rose | 11 | documented |
| Ferocactus alamosanus | (Britton & Rose) Britton & Rose | 10 | documented |
| Ferocactus flavovirens | (Scheidw.) Britton & Rose | 9 | documented |
| Ferocactus recurvus | (Mill.) Borg | 9 | documented |
| Ferocactus chrysacanthus | (Orcutt) Britton & Rose | 6 | documented |
| Ferocactus fordii | (Orcutt) Britton & Rose | 2 | below the evidence gate |
| Ferocactus pottsii | (Salm-Dyck) Backeb. | 2 | below the evidence gate |
| Ferocactus californicus | (Monv. ex Labour.) Borg | 0 | below the evidence gate |
| Ferocactus johnstonianus | Britton & Rose | 0 | below the evidence gate |
| Ferocactus lindsayi | Bravo | 0 | below the evidence gate |
| Ferocactus schwarzii | G.E.Linds. | 0 | below the evidence gate |
| Ferocactus tiburonensis | (G.E.Linds.) Backeb. | 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.