Perityle emoryi

Perityle emoryi is a species of flowering plant in the aster family known by the common name Emory's rockdaisy. It is native to the Southwestern United States, northwestern Mexico, and western South America. It is a common wildflower of the deserts, and can also be found in the coastal regions of the Californias, Sonora, and Sinaloa.

It grows in many types of habitat, it tolerates disturbance, and it can become somewhat weedy. it is an introduced species in parts of Hawaii. Its distribution is apparently expanding.

Description
Perityle emoryi, a polyploid plant, is quite variable genetically and in appearance. It is an annual herb growing 2 to 60 centimeters tall, its stem small, delicate, and simple, or thick, branching, and sprawling. It is usually hairy and glandular in texture. The alternately arranged leaves have blades of various shapes which are toothed or divided into lobes and borne on petioles.

The inflorescence is a single flower head or an array of a few or many heads. The head is hemispherical to bell-shaped and generally no more than a centimeter wide. The head has a center of many golden disc florets and a fringe of 8 to 12 white ray florets each just a few millimeters long. The fruit is an achene, usually with a pappus at the tip.

Distribution and habitat
Perityle emoryi is naturally distributed throughout southwestern North America and western South America, an amphitropical distribution.

In North America, it is distributed across the deserts of Arizona, California, Baja California, Baja California Sur, Nevada, Utah, Sonora, and Sinaloa. In Southern California it is also rarely found in coastal regions and the Peninsular Ranges, and becomes widespread throughout almost all the ecosystems of the Baja California peninsula, except for the Cape region and higher mountains.

Perityle emoryi is also found on the eastern Pacific island of Guadalupe.