Have you noticed these small orbs attached to the rubber rabbitbrush in the Spring Mountains? These tiny growths are galls, which are caused by irritation of plant cells after insects feed or lay eggs on the plants surface.
In this case, these galls are caused by a specific type of fruit fly (Aciurina trixa) and contain their larvae. This time of year, the larvae feed primarily on the gall itself and will emerge in mid-February. In most cases galls are not abundant enough to harm the plants.