  We report on high angular resolution, high precision spectropolarimetric
measurements of a decaying sunspot. The spot gradually lost its penumbra during
the course of three days. In the late stages of evolution where the only
remnant of the spot is a naked umbra, we find small-scale inhomogeneities in
the magnetic canopy surrounding it. The inhomogeneities are observed as
finger-like structures of weak and nearly horizontal magnetic fields extending
1-2 arcsec from the outer border of the umbra. These fields are not associated
with filamentary structures in continuum intensity, nor with conspicuous
Evershed flows. The Stokes profiles emerging from the fingers exhibit
blueshifts which we interpret as upward motions. This previously unknown fine
structure may be related to penumbral field lines that no longer carry strong
Evershed flows and rise to the chromosphere, producing the disappearance of the
penumbra at photospheric levels.
