The New Student's Reference Work/Emergence

Emer′gence (in plants), outgrowths from the surface of a plant, such as warts, prickles, etc., which involve in their origin the cortex as well as the epidermis. For example, the stem-prickles of the rose are emergences. A contrasting term is trichome, which is applied to structures derived entirely from the epidermis, as ordinary hairs.