On the hike up to see the famous Pinnacle Rock, we saw many of these whitish tiquilia plants growing on the slopes of the volcano. They contrast beautifully with the red/grey ashy soil. The light color comes from tiny hairs on the stems and leaves. They are one of the few plants that can survive in this arid zone.
Tiquilia is the genus name; there are several species endemic to the Galápagos, all of which are generally called tiquilia, or also “grey matplant,” which is a pretty dumb name, so let’s stick with tiquilia.