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Descurainia incana (Tansy Mustard) Foothills, montane.
Disturbed areas, meadows. Spring, summer. The flowers of this Mustard are even smaller than the tiny ones in the above species, but they, too, are in relatively large, terminal clusters. The plant is slender, tall, and has bright green, cut leaves. Descurainia incana is found infrequently in montane and higher altitudes in southwest Colorado but in some other mountainous areas it is more common. The plant was first described and named (probably Descurainia richardsonii) by Bernhardi and then was renamed Descurainia incana by Dorn. |
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Descurainia incana (Tansy Mustard) Foothills, montane.
Disturbed areas, meadows. Spring, summer. Two key distinguishing characteristics of D. incana are flattened seed pods and appressed pods (clasping the stem). In the photograph at left, the pods can be seen clasping the stem as the plant grows taller and new flower clusters bloom. |
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Descurainia
obtusa
(Blunt Tansy) Semi-desert.
Sandy shrublands, opening. Spring. 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. |
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Descurainia
obtusa
(Blunt Tansy) Semi-desert.
Sandy shrublands, opening. Spring. |
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Descurainia sophia Semi-desert.
Woodlands, shrublands, opening. Spring. In many woodland areas Descurainia sophia is a very 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, tiny, bright yellow flowers. Petals are only 2-3 millimeters long. The stem and leaves are often thickly clothed in a mass of very small, twisted, and often branched hairs. The petals are sparsely hairy. Descurainia sophia is a weedy, alien plant but a close inspection will show delicate leaf structure, lovely flowers, and very cute siliques (seed pods). The plant has a noticeably rank smell. 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. |
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Descurainia
sophia Semi-desert.
Woodlands, shrublands, opening. Spring. Pedicels (the stems of the seed pods) are 4-17 millimeters long. Siliques (the seed pods) are 15-30 millimeters long, may be green or maroon, and extend outward and upward. |
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Descurainia
sophia Semi-desert.
Woodlands, shrublands, opening. Spring. |
Range map © John Kartesz,
County Color Key
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Range map for Descurainia incana
Range map for Descurainia obtusa
Range map for Descurainia sophia |
Species present in state and native
Species present in state and exotic
Species not present in state
Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Eradicated
Questionable presence
