Mesembryanthemum crystallinum (common iceplant, crystalline ice plant) found adjacent to the road in at Portuguese Bend. I had thought since I first observed it that this was a native, due to the tenacious way that it clung to seaside crevices and novel appearance of dew drops on its leaves. I was wrong. It's actually an invasive plant. Wikipedia has useful information.
The plant usually uses C3 carbon fixation, but when it becomes water- or salt-stressed, it is able to switch to Crassulacean acid metabolism. Like many salt-tolerant plants, M. crystallinum accumulates salt throughout its life, in a gradient from the roots to the shoots, with the highest concentration stored in epidermal bladder cells. The salt is released by leaching once the plant dies. This results in a detrimental osmotic environment preventing the growth of other, non-salt-tolerant species while allowing M. crystallinum seeds to germinate.