roseness

[…] the ruling idea being that the knower cannot know the sensible things, but can only know the unchanging Forms of the things, and Plato means that there can be no rose absent roseness, for roseness makes a rose be a rose.

A rose comb is therefore regarded as a single comb in which roseness is present but peaness is absent; and a pea comb is similarly a single one where peaness is present and roseness is absent.