Stippling/Stippled in botany and plant pathology refers to areas of small dots, similar to the technique of stippling in art.
On leaves, an example would be the whitish dots that are the first sign of spider mite damage, resulting from their feeding removing the green pigment chlorophyll from plant cells.
On daylily flowers, stippling usually refers to small dots which may occur in the eyezone, over the entire surface of the tepals, along the edge of an eye, or only at the tip of the tepals.
This is not yet settled terminology among daylily hybridizers and use of this and other terms currently being applied to similar effects on flowers may continue to evolve.
In the following examples of stippled flowers the dark dots are anthocyanin (red, purple) pigment.