Glossary Details – Lecythidaceae

Glossary Details:

Placentation of Cariniana micrantha. Photo by C. Carollo.

Title: Placentation of Allantoma lineata. Photo by C. Carollo.

Description: Cat ear-shaped locule of Allantoma lineata based on Freitas 521 from Amazonas, Brazil. Note that the locules are longer than wide and that the upper left hand angle is acute. This species has a columnar type of placentation which means that the ovules arise from placental tissue that arises from most of the length of a more-or-less evenly expanded lower septum. The upper septum of this species develops into the tack-shaped columella of the fruit of this species.

Term:

Placenta columnar

Definition:

A type of placentation in which the lower septum is only slightly expanded more-or-less equally throughout its length as seen in a medial longitudinal section.

Notes:

Species of Allantoma, Cariniana, and Couratari have this type of placenta, and Bertholletia excelsa also displays this type but the lower septum is much shorter in this than it is in the first three genera.