Term:

Smooth
Definition:

A part of a plant, such as the bark or hypanthium, that does not have furrows or conspicuous outgrowth
Notes:

In the Lecythidaceae, smooth is usually used to refer to the bark or the pedicel/hypanthium. Note that smooth bark is never really 100% smooth but it is smooth than fissured, scalloped, or rought bark.
Related Terms:

Sulcate