  Ground-based telescopes coupled with adaptive optics (AO) have been playing a
leading role in exoplanet direct imaging science and technological development
for the past two decades and will continue to have an indispensable role for
the next decade and beyond. Over the next decade, extreme AO systems on 8-10m
telescopes will 1) mitigate risk for WFIRST-CGI by identifying numerous planets
the mission can spectrally characterize, 2) validate performance requirements
and motivate improvements to atmosphere models needed to unambiguously
characterize solar system-analogues from space, and 3) mature novel
technological innovations useful for space. Extremely Large Telescopes can
deliver the first thermal infrared (10 $\mu m$) images of rocky planets around
Sun-like stars and identify biomarkers. These data provide a future NASA direct
imaging flagship mission (i.e. HabEx, LUVOIR) with numerous exo-Earth
candidates and critical ancillary information to help clarify whether these
planets are habitable.
