phytomer

from The Collaborative International Dictionary of English v.0.48

Phytomer \Phy"to*mer\, Phytomeron \Phy*tom"e*ron\, n. [NL.
   phytomeron, fr. Gr. fyto`n plant + me`ros share.] (Bot.)
   An organic element of a flowering plant; a phyton.
   [1913 Webster]