Spines on plants are hard structures with sharp ends. Botanists use three different words, thorns, spines, and prickles. Thorns are the ends of branches that are hard and sharp. Prickles are on the outside of stems. There are many different kinds of spines, some on leaves, some grow instead of leaves.
Spines, prickles, and thorns protect plants from plant-eating animals. Some plants and animals, such as the acacia tree and giraffe have evolved in response to each other. The plants grow very long spines and the animals develop very long tongues to reach past the spines and feed on the leaves.
Prickles on rose stems
Spines on this Acacia grow below the leaves (the stem is sideways in the picture)
- Esau, K. 1965. Plant Anatomy, 2nd Edition. John Wiley & Sons. 767 pp.
- Llamas, K. A. 2003. Tropical Flowering Plants. Timber Press, Portland. 423 pp.
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