Phase of warmer climate within a glacial period, but of shorter duration (and thought to be less warm) than an interglacial. Warmth-demanding (thermophilous) species, e.g. Tilia (lime), are not represented in the pollen record, which shows Boreal affinities. The absence of thermophilous species may, however, be as much a consequence of the shorter time-span of an interstade as of the lack of warmth.