Lathyrus montanus – synonym of Lathyrus linifolius
Lemna polyrhiza – synonym of Spirodela polyrhiza
Leontodon taraxacoides – synonym of Leontodon saxatilis
Leucorchis albida – synonym of Pseudorchis albida
Leucorchis albida var. subalpina – synonym of Pseudorchis albida
Listera nephrophylla – synonym of Listera cordata
Lotus uliginosus – synonym of Lotus pedunculatus
Luzula campestris subsp. multiflora – synonym of Luzula multiflora
Luzula multiflora subsp. occidentalis – synonym of Luzula multiflora
Luzula subpilosa – synonym of Luzula campestris