Term:

Zygomorphic
Definition:

Capable of being divided into only two equal parts; a structure in which a line drawn through the middle will produce a mirror image of one side of the line to the other side of the line.
Notes:

In Lecythidaceae, used to describe the symmetry of flowers. Zygomorphic flowers are only found in the Neotropics. Species of Bertholletia, Cariniana, Corythophora, Couratari, Couroupita, Eschweilera, and Lecythis have zygomorphic flowers. There are two types of zygomorphic flowers in neotropical Lecythidaceae, obliquely zygomorphic (only found in species of Cariniana) and staminal ring zygomorphic (found in the remaining zygmorphic genera). An obliquely zygomorphic-flowered androecium has an extension on one side of a staminal tube. In contrast, a normally zygomorphic-flowered androecium has a prolongation of the abaxial side of the androecium that arises from the staminal ring.