Although it is dry most of the year and has spines up its branches, the Ocotillo is not a cactus since it grows true leaves. The plant is funnel shaped, with long, straight, mostly un-branched stems.
Leaves are bright green and appear after a rain storm.
The leaves and flowers die off as the soil dries. The bloom cycle may be repeated several times a year depending on the timing of rain storms. And it's not a lily. It's not closely related to any other plant of the Southwest desert. South of California, in old Mexico, it has one kin, the Boogum Tree, which is an even stranger plant.