Synonym:  Asclepias macrosperma. Asclepias involucrata.  (Milkweed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Sand, canyon washes, shrublands. Spring, summer.
Hunter Canyon, Utah, May 3, 2005.

The soft green of this lovely plant is due to downy hairs that cover the folded and twisting leaves.  Plants sprawl along the ground with flower clusters emerging from the ends of leaf stems.  Flowers are a greenish yellow and in a starburst sphere typical of plants in the Milkweed Family.  

In 1893 Alice Eastwood collected this species in Court House Wash in what is now Arches National Park.  She named it "macrosperma" for its large seeds.

Synonym:  Asclepias macrosperma. Asclepias involucrata.  (Milkweed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Sand, canyon washes, shrublands. Spring, summer.
Hunter Canyon, Utah, May 3, 2005.

Asclepias tuberosa (Butterfly Weed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Canyon washes, roadsides. Spring, summer.
Road to Needles District of  Canyonlands National Park, Utah, July, 25, 2008.

"Eye-catching", "symmetrical", and "bright orange" sum up this lovely plant.  Asclepias tuberosa is quite common in moist areas of the central and eastern United States, but is uncommon in the west, occurring primarily in the Four Corners states along roadsides and in washes.  The plant is, in the words of Intermountain Flora, "one of the most widely dispersed..., as well as one of the most beautiful, wildflowers of temperate North America....  Asclepias tuberosa is highly variable in habit, foliage, and flower-color."

"Tuberosa" refers to swellings on the roots.

Asclepias tuberosa (Butterfly Weed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Canyon washes, roadsides. Spring, summer.
Road to Needles District of  Canyonlands National Park, Utah, July, 25, 2008.

Asclepias tuberosa (Butterfly Weed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Canyon washes, roadsides. Spring, summer.
Road to Needles District of  Canyonlands National Park, Utah, July, 25, 2008.

Asclepias tuberosa (Butterfly Weed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Canyon washes, roadsides. Spring, summer.
Road to Needles District of  Canyonlands National Park, Utah, July, 25, 2008.

Asclepias tuberosa (Butterfly Weed)
Asclepiadaceae (Milkweed Family)

Semi-desert. Canyon washes, roadsides. Spring, summer.
Big Spring Trail, Canyonlands National Park, Utah, September, 10, 2005.

Ripening seed pods.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Asclepias macrosperma (Asclepias involucrata)

Range map for Asclepias tuberosa