exact: lado abaxial del primordio de hoja (Spanish)
A portion of vascular leaf primordium (PO:0000017) that is distal to the axis of the shoot apical meristem (PO:0020148) and develops into the abaxial side of the leaf lamina (PO:0020039). [source: POC:Brian_Atkinson, POC:curators, POC:Laurel_Cooper]
While the abaxial side of the leaf is usually the lower surface, the vascular leaves (PO:0009025) of some plants may not have an obvious adaxial or abaxial side such as the leaves of many xerophytic (arid-adapted) species. The adaxial and abaxial side may appear considerably more rounded and this could be due to early activity of the vascular leaf adaxial meristem (PO:0025401) and/or leaf abaxial meristem (PO:0025401). In other cases, such as Alstromeria, the leaves may be twisted or resupinate.