caudex

< /ˈkɔ dəˌsiz/, cau·dex·es. Botany.

1. the main stem of a tree, especially a palm or tree fern.
2. the woody or thickened persistent base of an herbaceous perennial.

noun plural -dices (-dɪˌsiːz) or -dexes

1. the thickened persistent stem base of some herbaceous perennial plants
2. the woody stem of palms and tree ferns

1. The thickened, usually underground base of the stem of many perennial herbaceous plants, from which new leaves and flowering stems arise.
2. The trunk of a palm or tree fern.