The discovery of coronal holes in the early 1970s was heralded as the
discovery of the mysterious M-regions responsible for recurrent geomag
netic activity. High-speed flow from the holes, sweeping past Earth on
successive solar rotations, was directly correlated with sustained in
creases in activity indices. We argue that this view of M-regions as c
oronal holes is incomplete because it ignores work dating from the 196
0s demonstrating that peak recurrent activity coincides with passage o
f corotating interaction regions between high- and low-speed flows. Th
us, in an important way, M-regions include the boundary between corona
l holes and coronal streamers, since streamers supply the slowest flow
s. In addition, we suggest that coronal mass ejections propagating thr
ough the streamer belt can contribute to the peak intensities of recur
rent storms. Finally, we demonstrate that both peak recurrent activity
and the following sustained activity that correlates with the high-sp
eed flows are controlled by the Russell-McPherron effect: They are pro
minent only when the azimuthal component of the Parker spiral field pr
ojects a southward component in Earth's tilted dipole frame.