induration. 1. the process of hardening or being hardened.
1 They're weak against the Ice and Water types in reference of erosion, which cause this elements to the ground. 2  They're immune against the Electric type because in real life, the ground is a natural sink of electrons.  The Bug type resists them because many bugs like worms live inside the ground and many of them eat it.
Ceanothus griseus horiz. 'yankee point' - durable groundcover reaches 2 to 3 feet tall and spreads 8 to 12 or more feet wide. Ground Cover - front yard street corners and back edge of property. I am on the road, photographing California native plants, and just too dang busy to think about anything else.