Celery-leaf Licorice-root, Celery-leaf Wild Lovage, Celery-leaved Lovage, Parsley-leaved Lovage: Ligusticum apiifolium (Synonym: Cynapium apiifolium)
Canby's Licorice-root, Canby's Lovage, Canby's Wild Lovage: Ligusticum canbyi (Synonyms: Ligusticum caeruleimontanum, Ligusticum leibergii) - Rays of the umbel 15-30. Plants typically with 2-3 umbels. Stems thick and strong, often with 1 well developed stem leaf. Leaves dissected into numerous segments wider than 3 mm and not linear in outline. Plants 50-120 cm high.
Fern-leaved Lovage: Ligusticum filicinum var. filicinum (Synonym: Ligusticum filicinum var. filicinum) - Rays of the umbel 12-20. Plants typically with 1 umbel, rarely 2 or 3. Stems weak and slender with 1 or more well-developed leaves. Leaves dissected into numerous more or less linear segments from 1-3 mm wide. Basal leaves 10-25 cm wide. Plants 50-100 cm high.
Gray's Licorice-root, Gray's Lovage, Sheep Wild Lovage: Ligusticum grayi (Synonyms: Ligusticum apiifolium var. minus, Ligusticum cusickii, Ligusticum purpureum, Ligusticum tenuifolium var. dissimilis, Pimpinella apidora var. nudicaulis) - Rays of the umbel 5-18. Plants typically with 2-3 umbels. Stems thick and strong, often with 1-2 reduced leaves. Leaves dissected into numerous segments wider than 3 mm and not linear in outline. Plants 20-60 cm high.
Slenderleaf Lovage, Slender-leaved Lovage: Ligusticum tenuifolium (Synonyms: Ligusticum filicinum var. tenuifolium, Ligusticum oreganum) - Rays of umbel 5-13. Stems slender with stem leaves lacking or with 1 much-reduced leaf. Leaves dissected into numerous more or less linear segments from 1-3 mm wide. Basal leaves less than 10 cm wide. Plants 10-60 cm high.