The Descurainia genus was named by Philip Webb (1793-1854) and Sabin Berthelot (1794-1880) in the mid-1800s.  Francois Descurain, 1658-1740, was a French botanist and pharmacist. (More biographical information.)

Descurainia obtusa (Blunt Tansy) 
Brassicaceae (Mustard Family)

Semi-desert. Sandy shrublands, opening. Spring.
Near Bluff, Utah, May 2, 2007.

Descurainia obtusa is fairly common through several counties in New Mexico and much more common in Arizona but it has only recently been discovered in Montezuma County, Colorado and San Juan County, Utah.  Leaves and fruit are rounded (obtuse) at their tips, and the fruit (in Mustards called a "silique") is abruptly contracted at its tip and somewhat at its base.  Flowers are minute but clustered so they do attract attention.

Edward Greene first named this plant Sophia obtusa around the turn of the 19th/20th century; it was renamed by Otto Schultz early in the 20th century.

Descurainia obtusa (Blunt Tansy) 
Brassicaceae (Mustard Family)

Semi-desert. Sandy shrublands, opening. Spring.
Near Bluff, Utah, May 2, 2007.

Descurainia pinnata
Brassicaceae (Mustard Family)

Semi-desert. Woodlands, shrublands, opening. Spring.
Canyons of the Ancients National Monument, April 1, 2005.

In many woodland areas Descurainia pinnata is the most common spring plant, often found in dense patches, sometimes scattered over large areas, but it also can be solitary.  The finely cut leaves appear early in the spring and are followed by a long, lanky plant topped with a tight cluster of numerous bright yellow flowers.  This is an easy plant to see as "just another weed", but it is native.  A close inspection will show delicate leaf structure, lovely flowers, and very cute siliques (seed pods).

Thomas Walter (1740-1788) gave this species its first name, Erysimum pinnatum, in 1788.  The species was renamed Descurainia pinnata by Nathaniel Britton (1859-1934) in 1894.

"Pinnata" from the Latin for "feather", describes the finely cut leaves.

Descurainia pinnata
Brassicaceae (Mustard Family)

Semi-desert. Woodlands, shrublands, opening. Spring.
Canyons of the Ancients National Monument, April 1, 2005.

Descurainia pinnata
Brassicaceae (Mustard Family)

Semi-desert. Woodlands, shrublands, opening. Spring.
Canyons of the Ancients National Monument, April 1, 2005.

Descurainia sophia (Tansy Mustard)
Brassicaceae (Mustard Family)

Foothills, montane. Disturbed areas, meadows. Spring, summer.
El Diente Trail, July 22, 2004.

The flowers of this Mustard are even smaller than the tiny ones in the above species, but they, too, are in relatively large, attractive terminal clusters. The plant is slender, tall, and has finely cut leaves.  It is conspicuous along foothills and mountain trails.

Linnaeus gave this species its original name of Sisymbrium sophia in 1753, and Philip Webb gave it its present name which was published by Kark Prantl in 1891.

Descurainia sophia (Tansy Mustard)
Brassicaceae (Mustard Family)

Foothills, montane. Disturbed areas, meadows. Spring, summer.
El Diente Trail, July 22, 2004.

Flattened seed pods can be seen developing along the stem as the plant grows taller and new flower clusters continue to elongate and bloom.

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 Descurainia obtusa

Range map for Descurainia pinnata

Range map for Descurainia sophia