Ledum was a genus in the family Ericaceae, including eight species of evergreen shrub native to cool temperate and subarctic regions of the Northern Hemisphere and commonly known as Labrador tea. It is now recognised as a subsection of section Rhododendron, subgenus Rhododendron, of the genus Rhododendron.
Ledum species often grow together with poisonous plants such as bog-laurel and bog-rosemary, but certain species (e.g. L. groenlandicum and L. palustre) are easily distinguished by the distinctive rust coloured fuzz on the bottom of leaves.
Recent genetic evidence has shown that the species previously treated in this genus are correctly placed in the genus Rhododendron, where they are now treated as Rhododendron subsect. Ledum. Because some of the species names used in Ledum could not be used in Rhododendron (the names already having been used for other species already in this large genus), new names had to be coined for them.
The species listed in genus Ledum (accepted and synonyms), with their current accepted names are:
| Ledum species | Author | GBIF status | TPL status | GBIF Accepted species | Author | GBIF status | TPL Accepted species | Author | TPL status | |
|---|---|---|---|---|---|---|---|---|---|---|
| Ledum | L. | Accepted | ||||||||
| Ledum angustifolium | Hort. ex Lavallée | Accepted | ||||||||
| Ledum buxifolium | Bergius | Synonym | Kalmia buxifolia | (Bergius) Gift & Kron | Accepted | |||||
| Ledum californicum | Kellogg | Synonym | Ledum glandulosum | Accepted | ||||||
| Ledum columbianum | Piper | Synonym | Accepted | Rhododendron columbianum | (Piper) Harmaja | Accepted | ||||
| Ledum decumbens | (Ait.) Lodd. | Synonym | Rhododendron tomentosum subsp. decumbens | (Aiton) Elven & D.F.Murray | Accepted | |||||
| Ledum decumbens | (Ait.) Lodd. ex Steud. | Synonym | Synonym | Rhododendron tomentosum subsp. decumbens | (Aiton) Elven & D.F.Murray | Accepted | Ledum palustre subsp. decumbens | Accepted | ||
| Ledum decumbens | Small | Accepted | Accepted | |||||||
| Ledum glandulosum | Nutt. | Synonym | Accepted | Rhododendron neoglandulosum | Harmaja | Accepted | ||||
| Ledum glandulosum subsp. glandulosum | Synonym | Ledum glandulosum | Accepted | |||||||
| Ledum glandulosum var. californicum | (Kellogg) C.L.Hitchc. | Synonym | Ledum glandulosum | Accepted | ||||||
| Ledum glandulosum var. glandulosum | Synonym | Ledum glandulosum | Accepted | |||||||
| Ledum groenlandicum | Oeder | Synonym | Synonym | Rhododendron groenlandicum | (Oeder) K.A.Kron & W.S.Judd | Accepted | Ledum palustre subsp. groenlandicum | Accepted | ||
| Ledum groenlandicum | Retz. | Accepted | ||||||||
| Ledum groenlandicum f. denudatum | Vict. & J.Rousseau | Accepted | ||||||||
| Ledum groenlandicum subsp. glandulosum | (Nutt.) Á.Löve & D.Löve | Synonym | Synonym | Rhododendron neoglandulosum | Harmaja | Accepted | Ledum glandulosum | Accepted | ||
| Ledum groenlandicum var. aridiphilum | D.Löve | Accepted | ||||||||
| Ledum hypoleucum | Kom. | Synonym | Synonym | Rhododendron diversipilosum | (Nakai) H.Harmaja | Accepted | Rhododendron hypoleucum | (Kom.) Harmaja | Accepted | |
| Ledum idahoensis | Accepted | |||||||||
| Ledum macrophyllum | Tolm. | Synonym | Accepted | Rhododendron diversipilosum | (Nakai) H.Harmaja | Accepted | ||||
| Ledum maximum | (Nakai) A.P.Khokhr. & M.T.Mazurenko | Synonym | Accepted | Rhododendron tomentosum | Harmaja | Accepted | ||||
| Ledum palustre | L. | Synonym | Accepted | Rhododendron tomentosum | Harmaja | Accepted | ||||
| Ledum palustre | Michx. | Synonym | Rhododendron groenlandicum | (Oeder) K.A.Kron & W.S.Judd | Accepted | |||||
| Ledum palustre f. decumbens | (Aiton) Y.L.Chou & S.L.Tung | Synonym | Ledum palustre subsp. decumbens | Accepted | ||||||
| Ledum palustre subsp. angustissimum | Worosch. | Synonym | Rhododendron subulatum | (Nakai) Harmaja | Accepted | |||||
| Ledum palustre subsp. decumbens | (Aiton) Hultén | Accepted | ||||||||
| Ledum palustre subsp. diversipilosum | Hara | Synonym | Ledum macrophyllum | Accepted | ||||||
| Ledum palustre subsp. groenlandicum | (Oeder) Hultén | Synonym | Accepted | Rhododendron groenlandicum | (Oeder) K.A.Kron & W.S.Judd | Accepted | ||||
| Ledum palustre var. angustifolium | Hook. | Accepted | ||||||||
| Ledum palustre var. angustum | E.A.Busch | Synonym | Ledum palustre | Accepted | ||||||
| Ledum palustre var. decumbens | Aiton | Synonym | Ledum palustre subsp. decumbens | Accepted | ||||||
| Ledum palustre var. diversipilosum | Nakai | Synonym | Synonym | Rhododendron diversipilosum | (Nakai) H.Harmaja | Accepted | Ledum macrophyllum | Accepted | ||
| Ledum palustre var. latifolium | (Jacq.) Hook. | Synonym | Rhododendron groenlandicum | (Oeder) K.A.Kron & W.S.Judd | Accepted | |||||
| Ledum palustre var. latifolium | (Jacq.) Michx. | Synonym | Rhododendron groenlandicum | (Oeder) K.A.Kron & W.S.Judd | Accepted | |||||
| Ledum palustre var. maximum | Nakai | Synonym | Ledum maximum | Accepted | ||||||
| Ledum palustre var. palustre | Synonym | Ledum palustre | Accepted | |||||||
| Ledum palustre var. subulatum | Nakai | Synonym | Rhododendron subulatum | (Nakai) Harmaja | Accepted | |||||
| Ledum serpyllifolium | Accepted | |||||||||
| Ledum subulatum | (Nakai) A.P.Khokhr. & M.T.Mazurenko | Synonym | Synonym | Rhododendron subulatum | (Nakai) Harmaja | Accepted | Rhododendron subulatum | (Nakai) Harmaja | Accepted |
LedumRhododendronOther
Natural hybrids (nothospecies) also occur.
Some species (e.g. L. groenlandicum) have been used to produce Labrador tea. Other species have varying levels of toxicity (e.g. L. glandulosum). Evergreen Labrador Tea grows slowly, but retains its leaves year-round. Users should take care not to over-harvest leaves from any single plant.