prickle

noun

A hard, pointed outgrowth from the surface of a plant, small, weak, and spine-like, arising from the epidermis, involving several layers of cells but not containing a vein and which may cover the surface of a plant. It contains cortical and vascular tissue and is not regarded as an epidermal outgrowth, usually more slender than a thorn. This is the correct term for rose `thorns`. Cf. spine, thorn.