Q. Do roses have thorns, spines or prickles?
In everyday language, people tend to call any sharp appendages on a stem thorns. In botanical language, however, there are three different classifications of these sharp points. They are grouped according to the plant material from which they develop. Thorns develop from shoot material, spines are modified leaf structures, and prickles form from the plant's epidermis and cortex (outermost layers).
Prickles are what roses have. Because they are extensions of the plant's outer covering, prickles contain no vascular material and so are easier to remove than thorns or spines. Rose prickles, usually sickle-shaped, enable rose plants to hang onto other vegetation when growing over it. However, the densely-packed prickles on Rosa rugosa and Rosa pimpinellifolia, sandy soil roses, are straight.
Examples of plants with spines include barberry and cactus. Honey locust trees and gooseberries have thorns.
In nature, the purpose of thorns, spines and prickles is to protect plants from would be predators. However, despite the presence of prickles, roses are frequently browsed by deer.
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- Courtesy of NYBG Plant Information Service