Term:

Plane
Definition:

Referring to a structure that is flat, even, or level with the surface of the structure in which it occurs; i.e., without projectiing above the surface of an organ.
Notes:

In Lecythidaceae, usually referring to the veins of leaves or seeds. Differs from submerged in visibility; e.g., a submerged vein can not be seen whereas a plane vein is visible. The differences among salient, prominent, prominulous, plane, and submerged are based on the degree of elevation, e.g., between the top of a vein and the surface of the organ of which it is a part. These features grade into one another but generally speaking a salient vein is one that projects 0.5 to several millimeters above the surface, a prominent vein is one that is distinct and raises between 0.1 and 0.4 mm above the surface, and a prominulous vein is one that is raised so little that it is only perceived when a finger nail is run along the blade at a right angle across it. If nothing blocks the fingernail, the vein is plane and if a depression is perceived it is impressed. If a vein is not seen, it is said to be submerged in the tissue. In neotropical Lecthidaceae, this terminology is mostly applied to the the veins of leaves and seeds.