Linnaeus named this genus in 1753, and Sereno Watson named this species in 1871 from a specimen collected by Thomas Nuttall near the Green River in 1834.  The plant was for several decades in the mid-1800s known as Acerates latifolia as named by Torrey and Fremont in 1845 from a collection made by Fremont on the Green River in 1844.

  Aesculapius, a legendary Greek physician, was the Greek God of Medicine.  Members of the genus Asclepias have been used medicinally for millennia and are sometimes used in modern herbal teas.

Asclepias cryptoceras  (Pallid Milkweed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Sand, shrublands. Spring.
Above Yellow Jacket Canyon, April 23, 2009.
Canyons of the Ancients National Monument, May 23, 2009.

Asclepias cryptoceras grows on a variety of dry soil types from the Sagebrush to Aspen zones. Flowers are pale yellow with maroon hoods.  (See below.)   The plant sprawls along the ground and sends out clusters of flowers as it grows.

Leaves of Asclepias cryptoceras are very similar to those of Mirabilis multiflora  (photograph immediately below) and the two are found in the same habitat so before they flower the two plants could be confused with each other.

Linnaeus named this genus in 1753.  "Asclepias" was a legendary Greek physician and the Greek god of medicine; "cryptoceras" means "hidden horn" and refers to a horn-like projection in the hood of the flower. 

Asclepias cryptoceras  (Pallid Milkweed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Sand, shrublands. Spring.
Canyons of the Ancients National Monument, May 23, 2009.

This flower is just opening; the buffy-yellow sepals and petals reflex and the strange inner parts of the flower will open.  (Click to see Waynesword web site for information about the structure of Milkweed flowers.)

Asclepias cryptoceras  (Pallid Milkweed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Sand, shrublands. Spring.
Above Yellow Jacket Canyon, April 23, 2009.

The milky juice characteristic of Asclepiadaceae oozes from the plant where I accidentally cracked a leaf base.