Plant Story - Flixweed, Tansy Mustard, Herb Sophia, Descurainia sophia, Weedy Spring Mustard

 As a group, the plants in the mustard or cabbage family, Brassicaceae, are cool weather plants, growing well early in the spring, flowering as the temperatures warm, going to seed in the heat of summer. Familiar mustards are cabbage (Brassica oleracea), broccoli (Brassica oleracea), and mustard itself (mustards are species of Brassica, Rhamphospermum and Sinapsis). These edible mustard family plants were domesticated in Eurasia and they are a small selection of the more than 3,700 species worldwide. North America has 634 native species in the mustard family. It also has more than 100 exotic mustards. 

Flixweed, Descuriania sophia

the plant this blog is about 

It is far easier to see the exotic mustards, because they are weedy and tend to appear along roadsides and in disturbed areas. 

But, oh, they are difficult to tell apart! 

Members of the mustard are relatively easy to recognize. In addition to flowering in spring, almost all have four petals in a cross pattern. An alternative name for the family is Cruciferae, referring to that cross shape of the flowers. Most mustards have yellow flowers, some have white flowers, and a minority are blue-purple. So flower shape isn't helpful and flower color will only help you identify one or two species. Mustards have diverse and interesting seed pods, helpful in identification, if the plant has seeds. The key in Ackerfield's Flora of Colorado begins with the type of hairs on the plant. So you need to have the plant, unless the photo was extremely close-up and detailed. 

Dame's rocket, Hesperis matronalis, relatively easily identified--
because of the flower color--but an invasive exotic mustard

Still, you can work out the names of the mustards one species at a time. Colorado has 137 native mustards and 50 introduced ones. There are a lot to learn.

Flixweed, Descurainia sophia
a bit over 2' tall

Here is flixweed, also called tansy mustard and herb sophia, Descurainia sophia, a weedy mustard from Europe. It appeared along a path in my yard, suggesting it was exotic and carried in on shoes. It is small and the leaves are feathery. The finely divided leaves are quite different from many other yellow mustards, letting me spot it picture books of weeds. Then I went to more technical works, to compare the details, to make sure it was this species and not a closely-related one.

Flixweed turns out to be quite interesting. It came to North America, probably stowed away in grain, more than 200 years ago and is now found all over the continent including well north into Canada and south into Mexico, except, curiously, Alabama and Florida. The genus Descurainia has eight North American species, all native except for this one. Ackerfield gives tansy mustard for the common name of all the natives and calls D. sophia flixweed. The USDA Plants database calls all the natives tansy mustard and this exotic, herb sophia. 

Flixweed, Descurainia sophia

Descurainia honors French botanist Francois Descourain (1658-1740). Sophia is Greek for wisdom. In this case, it was probably included as the species epithet because the plant was once called Sophia multifida, so the botanist that moved it into Descurainia conserved the name sophia. Naming it Sophia originally, by Linnaeus, turned the common name into the scientific name because in many parts of Europe, the plant was called herb sophia. 

The three common names, flixweed, tansy mustard, and herb sophia, seem about equally used, so if you are looking for this plant, try all three. 

Flixweed has been used as a food and medicinal in Europe, and since its arrival, in North America, for centuries. The leaves are eaten cooked and are more palatable when young. The seeds are particularly useful, gathered and pounded into flour or mixed with flour to make bread, or as a thickener. The seeds were also made into traditional summer drinks, in Iran and elsewhere. They are edible raw or cooked. The seeds can be substituted for commercial mustard, or sprouted and eaten wherever sprouts are used. 

Divided leaves of flixweed, Descurainia sophia

Herb sophia has a long history of medicinal uses. It has been applied to constipation, hemerrhoids, impotence, edyma, upper respiratory problems ranging from from hoarseness and sore throats to asthma, and for many other ailments. A recent review (Nimrouzi and Zarshenas, see References) found support for anti-infammatory, antioxidant, and analgesic effects, as well as anthelmintic (drives out worms) action, but wrote that other claims remain untested. It appears to be an effective medicinal, which suggests that it should be eaten in moderation. 

Flixweed, Descurainia sophia

This is a pretty plant with rather small flowers which, because they are clustered, are quite visible. It spreads by seeds, aggressively, but is edible and medicinal. Native tansy mustards have been widely used by Native Americans and settlers for food and medicine for centuries in very much the same ways that flixweed is used. I recommend discouraging this exotic weedy plant, in favor of its native relatives. But flixweed is so widespread that it is probably in North America (and, actually, all over the world) to stay. 

Comments and corrections welcome.

References

Ackerfield, J. 2023. Flora of Colorado. 2nd edition. BRIT Press, Fort Worth, Texas. 

Common Tansymustard. Descurainia sophia (L.) Webb ex Prantl. no date given Montana Plant Life link(Accessed 5/8/24).

Nimrouzi, M. and M. M. Zarshenas. 2016. Phytochemical and pharmacological aspects of Descurainia sophia Webb ex Prantl: modern and traditional applications. Avicenna J. Phytomed. 6(3): 266-272. link (Accessed 5/10/24).

Whitson, T. D. editor. 1992. Weeds of the West. Western Weed Science Society. Newark, California. 

Kathy Keeler

A Wandering Botanist

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