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 |
|---|---|---|---|
| Hydrogalium elongatum | (C.Presl) Kadereit & Schneew. | 917 | documented |
| Hydrogalium palustre | (L.) Kadereit & Schneew. | 827 | documented |
| Hydrogalium claytonii | (Michx.) Kadereit & Schneew. | 115 | documented |
| Hydrogalium perpusillum | (Hook.f.) Kadereit & Schneew. | 52 | documented |
| Hydrogalium confertum | (Hook.f.) Kadereit & Schneew. | 43 | documented |
| Hydrogalium labradoricum | (Wiegand) Kadereit & Schneew. | 18 | documented |
| Hydrogalium antarcticum | (Hook.f.) Kadereit & Schneew. | 6 | documented |
| Hydrogalium platygalium | (Maxim.) Kadereit & Schneew. | 6 | documented |
| Hydrogalium pusillum | (Hook.f.) Kadereit & Schneew. | 6 | documented |
| Hydrogalium minimum | (Hook.f.) Kadereit & Schneew. | 3 | documented |
| Hydrogalium involucratum | (Wahlenb.) Kadereit & Schneew. | 2 | below the evidence gate |
| Hydrogalium laevigatum | (L.) Kadereit & Schneew. | 2 | below the evidence gate |
| Hydrogalium gunnii | (Hook.f.) Kadereit & Schneew. | 1 | below the evidence gate |
| Hydrogalium subsimplex | (Hook.f.) Kadereit & Schneew. | 1 | below the evidence gate |
| Hydrogalium acuminatum | (I.Thomps.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium ambly | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium asthenes | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium bargyli | (Gomb.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium brevipes | (Fernald & Wiegand) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium charophyton | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium cunninghamii | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium cymulosum | (Post) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium euryphyllum | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium gemellum | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium geminifolium | (F.Muell.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium gracile | (C.A.Mey.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium hoskingii | (I.Thomps.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium innocuum | (Miq.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium karakulense | (Pobed.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium libanoticum | (Boiss.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium maximoviczii | (Kom.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium oblanceolatum | (I.Thomps.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium polymerum | (I.Thomps.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium scioanum | (Chiov.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium shikokianum | (Nakai) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium stenophyllum | (Baker) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium suave | (Fisch., C.A.Mey. & Avé-Lall.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium subulifolium | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium syrticola | (Miq.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium tanganyikense | (Ehrend. & Verdc.) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium tetraphyllum | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium trianae | (Wernham) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium wimmeranum | (Airy Shaw & Turrill) Kadereit & Schneew. | 0 | below the evidence gate |
| Hydrogalium xylorrhizum | (Nábělek) Kadereit & Schneew. | 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.