More Urban Species: Wormseed

[urbpan]

American Wormseed Chenopodium (Dysphania) ambrosoides

On the Fourth of July a coworker asked me "What's the name of that weed that smells like kerosene?" Well, here it is only three and a half months later and I have an answer. But before I go into it, I need to express how strange it is to me that after several years paying attention to the wild plants of my city, that one with such a distinct field marking (the smell) should have eluded me until now.

At my workplace (an animal facility in a large city park), this weed is exceedingly common. Once I was made aware of it, I found it in several locations--growing from cracks in the pavement, along pathways, and even in the bare stone dust of an unused animal enclosure. And yet I still have not encountered it anywhere in Boston outside of the park. And its smell is really really distinctive, closer I would say to turpentine than to kerosene. No doubt on an Urban Nature Walk or casual excursion somewhere I will find it again, and know what it is, but why I have not before is a mystery.

The plant is known as Epazote in its native range in Mexico and Central America, and as it has appeared as a weed all around the world, it has accumulated a number of other common names. Mexican Tea seems to be well traveled nickname, but names referring to its use as a purge for intestinal worms prevail, with homages to Saint Mary coming in second. Along with its use as a vermifuge it has been deployed as an anti-flatulent ingredient in foods, and simply as a spice for those who like the tang of lighter fluid in their diet.

The primary active ingredient is Ascaridole, a turpene (ah, we see why it smells of turpentine) which is of course toxic in large doses, and isolated and concentrated, is explosive. An array of other interesting phytochemicals hide in this simple weed, and "oil of chenopodium" has long been available as a cure for hookworm and others. Be advised: "In mammals, if given in sufficient dose, it depresses the spinal cord and finally kills by arrest of respiration."


"Chenopodium" means "goose foot." The leaf of both wormseed and lambsquarters is more or less goose foot shaped.

Another Chenopodium, lambsquarters, has been discussed here before. The plants are similar, though lambsquarters appears to be able to grow taller, given enough space. Lambsquarters contains many of the same chemicals as wormseed, but in much smaller amounts, making it more of a culinary plant and less of a pharmacological curiosity.


Presumably, those seen in July were flowering, while these October plants are clearly bearing fruit.

Sources and further reading:
Herbal uses, from Cornell: http://www.ansci.cornell.edu/plants/medicinal/epazote.html
A more colloquial herbal: http://www.henriettesherbal.com/eclectic/usdisp/chenopodium_oleu.html
The biological properties of ascaridole: http://www.ars-grin.gov/cgi-bin/duke/chemical.pl?ASCARIDOLE
Where in North America it is found (hint: almost everywhere): http://plants.usda.gov/java/profile?symbol=CHAM

Comments

[buboniclou.livejournal.com]

Oh man, I love me some epazote. The local taqueria puts it in their quesadillas. They are awesome. I've never noticed the lighter-fluid smell, though. I wish we had some in our backyard! All we get weed-wise is knotweed and pigweed and VA creeper and ivy and...

[(Anonymous)]

That's funny. I found out about epazote when some Mexican guys who were working on the block here in Brooklyn stopped to pick some that was growing around the base of the street trees. They said they used it in cooking, so we tried it and it's really good. The next time I saw growing was it was in Somerville, Mass. in a Portugese neighborhood, across the street from some little park. It seemed a lot like Brooklyn, kind of scruffy and low-rise urban. I wonder if it spreads naturally or if people bring it and plant it.