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Mountain tansymustard

Scientific Name:
Descurainia incana
Native Name(s):
  1. Northern Paiute: atsa (Fowler 1989); asa (Fowler 1989)
  2. Klamath: Chēp'-äs (Coville 1897)


Descurainia incana is an annual, biennial or perennial herb. The stem is erect with many distal branches. Leaves are basal and widely lanceolate to oblanceolate or ovate in shape and pinnately divided. The petals are yellow and oblanceolate. Fruits are erect on long appressed pedicels, with glabrous valves and a mid-veined septum. Seeds are ellipsoid to narrowly oblong and are formed in a single row of 14 to 22. This species blooms from May to September.

Identification Tips

Descurainia incana can be distinguished by its appressed seeds and erect to erect ascending pedicel.

Starch granules

Starch granule analysis in process.


Descurainia incana grows at elevations from 100 to 3500 m in open sites, meadows, sagebrush scrub, open aspen groves, and roadsides.


This species grows across the western and northeastern portions of the United States and Canada.

Descurainia incana was used as food by gathering the seeds, and roasting them or grinding them into flour for bread. 
As food
Northern Paiute: "[In regards to the seeds of atsa (tansy mustard)] atsa is an extremely small seed.  A heap of atsa seeds were put in the winnowing basket and roasted with charcoal.  They were roasted until they smelled good.  The charcoal was thrown out and the seeds allowed to cool and then they were ground on the metate.  Then it was mixed with cold water, using a spoon (soko'o).  The fan-shaped winnowing basket, closely woven, used to clean atsa seeds is called samu'na." (Fowler 1989:47) 
Northern Paiute: "[In regards to the seeds of atsa (tansy mustard)] asa ripens in July and is gathered at that time.  It is stored for the winter.  Asa has yellow blossoms and grows in the river valleys.  Not it grows in with alfalfa.  Pull the whole plant and stack it up in piles to dry in the sun.  When the seeds are loose, they are crushed between the hands to get out the seeds (red in color and very bitter).  You take the husks off this way.  Put the seeds in a cooking basket with hot stones and keep it moving.  When they cook they pop.  Then they know that it is cooked and the stones were taken out.  The cooked seeds are put out to dry in the sun.  They are ground on the metate into a meal.  Their bitterness is taken out by putting the meal in a cooking basket and mixing it with water.  It is kneaded like bread.  Add some more water and yellow scum comes to the top.  This is removed and the operation is repeated until all the bitterness is out of it.  Then more water is added to make a fine batter.  This is drunk for it is too water to be eaten with the fingers." (Fowler 1989:47) 
Klamath: "Chēp'-äs.- A slender, branching annual, commonly 25 to 50 cm. (10 to 20 inches) high, with pinnatifid, canescent leaves, yellow flowers, and slender racemes of narrow, divergent pods.  It occurs in open, upland soils, often as a weed in cultivated fields.  The seeds, called chēp'-säm, are parched and ground for food." (Coville 1897:96-97) 
Distribution Map: