Exactly, from my reading, they seem to be geared exactly for their alpine environment. Living in pockets on rock outcroppings they probably dont get sun all day, but are geared to take full advantage of intense direct sun for a few hours. Keep in mind that the sun at elevations where they evolved is even more intense than sun around sea level, but being tucked among the rocks means they probably dont get it all day.
This also may mean that during intense heat+sun they need more water than usual.
