Term:

Submerged
Definition:

A structure, such as a vein, emeshed in the tissue in which it occurs to such an extent that it is not visibile; usually referring to leaf veins that are not visible and not projecting above the surface of the leaf blade.
Notes:

In Neotropical Lecythidaceae, examples of submerged veins are the quaternary and higher order veins of all species of Grias with the exception of G. subbullata. This feature is also found periodically, but not universally, in other genera of neotropical Lecythidaceae. 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.