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 |
|---|---|---|---|
| Melocactus intortus | (Mill.) Urb. | 64 | documented |
| Melocactus harlowii | (Britton & Rose) Vaupel | 58 | documented |
| Melocactus curvispinus | Pfeiff. | 51 | documented |
| Melocactus macracanthos | (Salm-Dyck) Link & Otto | 22 | documented |
| Melocactus peruvianus | Vaupel | 14 | documented |
| Melocactus holguinensis | Areces | 12 | documented |
| Melocactus matanzanus | León | 12 | documented |
| Melocactus zehntneri | (Britton & Rose) Luetzelb. | 9 | documented |
| Melocactus nagyi | Z.Mészáros | 7 | documented |
| Melocactus ernestii | Vaupel | 6 | documented |
| Melocactus pedernalensis | M.M.Mejía & R.G.García | 6 | documented |
| Melocactus pachyacanthus | Buining & Brederoo | 5 | documented |
| Melocactus lemairei | (Monv. ex Lem.) Miq. ex Lem. | 4 | documented |
| Melocactus neryi | K.Schum. | 3 | documented |
| Melocactus santiagoensis | D.Barrios & Majure | 3 | documented |
| Melocactus caroli-linnaei | N.P.Taylor | 2 | below the evidence gate |
| Melocactus schatzlii | W.Till & R.Gruber | 1 | below the evidence gate |
| Melocactus smithii | (Alexander) Buining ex G.D.Rowley | 1 | below the evidence gate |
| Melocactus × albicephalus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus × bozsingianus | Antesberger | 0 | below the evidence gate |
| Melocactus × horridus | Werderm. | 0 | below the evidence gate |
| Melocactus acispinosus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus acunae | León | 0 | below the evidence gate |
| Melocactus amethystinus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus andinus | R.Gruber ex N.P.Taylor | 0 | below the evidence gate |
| Melocactus azureus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus bahiensis | (Britton & Rose) Luetzelb. | 0 | below the evidence gate |
| Melocactus bellavistensis | Rauh & Backeb. | 0 | below the evidence gate |
| Melocactus brederooanus | Buining | 0 | below the evidence gate |
| Melocactus broadwayi | (Britton & Rose) A.Berger | 0 | below the evidence gate |
| Melocactus concinnus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus conoideus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus deinacanthus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus estevesii | P.J.Braun | 0 | below the evidence gate |
| Melocactus evae | Z.Mészáros | 0 | below the evidence gate |
| Melocactus ferreophilus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus glaucescens | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus inconcinnus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus lagunaensis | (Z.Mészáros) D.Barrios & Majure | 0 | below the evidence gate |
| Melocactus lanssensianus | P.J.Braun | 0 | below the evidence gate |
| Melocactus levitestatus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus longicarpus | Buining & Brederoo | 0 | below the evidence gate |
| Melocactus mazelianus | Říha | 0 | below the evidence gate |
| Melocactus natalensis | (P.J.Braun & Esteves) N.P.Taylor | 0 | below the evidence gate |
| Melocactus oreas | Miq. | 0 | below the evidence gate |
| Melocactus paucispinus | Heimen & R.Raul | 0 | below the evidence gate |
| Melocactus perezassoi | Areces | 0 | below the evidence gate |
| Melocactus praerupticola | Areces | 0 | below the evidence gate |
| Melocactus radoczii | Z.Mészáros | 0 | below the evidence gate |
| Melocactus salvadorensis | Werderm. | 0 | below the evidence gate |
| Melocactus sergipensis | N.P.Taylor & Meiado | 0 | below the evidence gate |
| Melocactus stramineus | Suringar | 0 | below the evidence gate |
| Melocactus violaceus | Pfeiff. | 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.