  Svestka (Solar Phys. 1989, 121, 399) on the basis of the Solar Maximum
Mission observations introduced a new class of flares, the so-called flare
hybrids. When they start, they look as typical compact flares (phase 1), but
later on they look like flares with arcades of magnetic loops (phase 2). We
summarize the features of flare hybrids in soft and hard X-rays as well as in
extreme-ultraviolet; these allow us to distinguish them from other flares.
Additional energy release or long plasma cooling timescales have been suggested
as possible cause of phase 2. Estimations of frequency of flare hybrids have
been given. Magnetic configurations supporting their origin have been
presented. In our opinion, flare hybrids are quite frequent and a difference
between lengths of two interacting systems of magnetic loops is a crucial
parameter for recognizing their features.
