This was on the way down from Diamond Head, an extinct volcano near Waikiki. It's not a long hike, but it's a dry hot climate, there's very little shade, there are 173 steps (it's paved all the way), and we had to get to the airport so we did a speed tour. A girl in front of us stopped her friends near these plants and said, "Hey, those are those poky things!", a statement of the obvious which for some reason struck me as pretty funny.

Anyone know what the plant is really called?