PENTAMEROUS
pentamerous
(adjective) divided into five parts; specifically, having each floral whorl consist of five (or a multiple of five) members; “pentamerous flowers”
Source: WordNet® 3.1
Etymology
Adjective
pentamerous (not comparable)
(botany) In five parts; made up of five parts.
Source: Wiktionary
Pen*tam"er*ous, a. Etym: [Penta- + Gr.
1. (Biol.)
Definition: Divided into, or consisting of, five parts; also, arranged in
sets, with five parts in each set, as a flower with five sepals, five
petals, five, or twice five, stamens, and five pistils.
2. (Zoöl.)
Definition: Belonging to the Pentamera.
Source: Webster’s Unabridged Dictionary 1913 Edition