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This is a non-native invasive species.

Chorispora tenella

Chorispora tenella (Purple Mustard)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Fields, woodlands, openings. Spring.
Hidden Valley Trail, Utah, May 10, 2007.

Chorispora tenella

Chorispora tenella (Purple Mustard)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Fields, woodlands, openings. Spring.
Cortez, Colorado, April 6, 2005.

In early spring, fallow farm fields and even wilderness areas are often carpeted in the soft purples of Chorispora tenella, an Asian invasive species that has found a new home it really likes.  The glow lasts for many weeks as the plant grows taller and new flowers emerge along the raceme.  

A myriad of flowers is followed, unfortunately, by more than a myriad of seeds encased in seed pods about one-and-a-half inches long and upward curved.  Seeds over-winter and sprout in the early spring, once again carpeting the ground.  

Chorispora tenella has a peculiar odor, often described as "musky", but I find the odor oddly pleasant.  The first time I smelled it I thought of the smell of Crayolas warmed and melting in the sun.  I still call it the "Crayola Plant". For many years I thought the Crayola smell emanated from the flowers, but in 2009 I came across a large patch of the plant before it flowered and the familiar Crayola smell wafted down the trail to me before I ever saw the plants.

The Greek "Chori", "separate", and " spora", "seed", refers to the constricted seed shape. "Tenella" means slender and could refer to the overall plant or flower or seed shape, all of which are slender.  The plant was named Raphanus tenellus in 1776 by Peter von Pallas (1741-1811) from Eurasian specimens and was renamed Chorispora tenella in 1821 by Augustin Pyramus de Candolle (1778-1841). Its was first collected in Utah in 1937.

See Strigosella africana for a similar species.

Chorispora tenella

Chorispora tenella

Chorispora tenella(Purple Mustard)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Fields, woodlands, openings. Spring.
Cortez, Colorado, April 6, 2005.

Blue-pink to purple petals extend outward, often with twists.

Gleaming glandular hairs are common on most plant parts and they are probably the source of the Crayola smell.

Leaves are commonly sinuate-dentate (wavy-edged with teeth) and various floras indicate the leaves may also be "deeply sinuate-dentate", "pinnatifid", or even "entire".

 

Chorispora tenella

Chorispora tenella (Purple Mustard)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Fields, woodlands, openings. Spring.
Cortez, Colorado, April 6, 2005.

Hidden Valley Trail, Utah, May 10, 2007.

A myriad of curved seed pods will produce a myriad of plants next year.

Chorispora tenella is a tenacious annual.

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 Chorispora tenella