Another fabulous gilia, and very distinctive, is Gilia subnuda. It is widespread on slick rock throughout the American Southwest--at least Canyonlands and the San Rafael Swell. It's main claims to fame are its Lewisia like, leathery, nearly succulent rosettes, it's everblooming habit (in the garden with a bit of water, it can bloom all summer). It is also perennial, although not a Methuselah.
It lasted two or three years for me before pooping out. It didn't self sow, and I neglected to sow seed, so it's one I must recollect.