Plants — J
- Jacaranda jacarandas
- Jacaranda caerulea
- Jacaranda caroba
- Jacaranda decurrens
- Jacaranda mimosifolia Black Poui
- Jacobaea vulgaris Common Ragwort
- Jasminum
- Jasminum grandiflorum Catalan Jasmine
- Jasminum nudiflorum Winter Jasmine
- Jasminum officinale
- Jasminum sambac
- Jateorhiza palmata jateorhiza
- Jatropha curcas Barbados nut
- Jatropha integerrima
- Juglans Nogal
- Juglans cinerea Butternut
- Juglans regia Carpathian Walnut
- Juncus Common Rush
- Juncus effusus Common Rush
- Juniperus Cedar
- Juniperus communis Common Juniper
- Juniperus oxycedrus Cade Juniper
- Juniperus scopulorum Colorado juniper
- Justicia adhatoda Malabar Nut
- Justicia gendarussa