In
botany, an evergreen plant is a plant that has
leaves all year round. This contrasts with
deciduous plants, which completely lose all their foliage for part of the year. Leaf persistence in evergreen plants may vary from only a few months (with new leaves constantly being grown and old ones shed), up to a maximum of 45 years in
Great Basin Bristlecone Pine Pinus longaeva . However, very few species show leaf persistence of over 5 years. One additional special case exists in
Welwitschia, an African
gymnosperm plant which produces only two leaves, which grow continuously throughout the plant's life but gradually wear away at the apex, giving about 20–40 years' persistence of leaf tissue.
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