Thorns, spines and prickles

While, in normal conversation, these terms are interchangeably used for any sharp protuberance from a plant’s stem, they are technically all slightly different:


These are stems growing from axillary buds which have been modified to form sharp points. Thorns are found on hawthorns (Crataegus species).


Prickles are specialised growths originating from the epidermis (outer layer) cells of the stem. They are used for protection and, often, to assist the plant in scrambling over other vegetation. Roses have prickles.


Spines are leaves, or parts of leaves, which have been modified into thin spikes to protect the plant. They are often found replacing ‘normal’ leaves entirely in plants used to living in very dry conditions to reduce water loss. In these cases the plant’s stem has evolved to do the photosynthesis to make up for the reduction in the leaf surface area. Cacti, hollies (Ilex) and barberries (Berberis) are examples of plant which have spines.