Yucca brevifolia Engelm. Joshua Tree
Stem to 9m or more, often branching. Flowers green, tinged yellow to cream with an unpleasant scent.

Pollination is by the yucca moth, Tegeticula spp., which lives in the flowers; it gathers up pollen from one flower, before flying to another and laying an egg in the stigma. It then puts one of the balls of pollen it has gathered on top of the egg. The pollen fertilizes the flower, and the larva feeds on some of the developing seeds, leaving others to ripen normally.
California to South West Utah Zone 7