You can't miss them. Big white flowers along the roadside in the eastern Rocky Mountains and out onto the plains.
|crested prickly poppy, Argemone polyanthemos|
|poppy, Papaver sp.|
|California poppy, Eschscholzia californica|
Native to the western U.S.
Crested prickly poppy can be seen from North Dakota to Texas, east to Kansas and Nebraska (That distribution is from the Flora of North America. The USDA gives it a wider distribution (see USDA map). I cannot find crested prickly poppy listed as a weed anywhere, although it grows best on disturbed sites.
Crested prickly poppies are pretty easily recognized. The flowers are open with white petals and a thick cluster of bright yellow stamens around stigmas that are reddish. The foliage runs to blue shades. The leaves usually have a lighter line running down the center and oh, yes, the leaves and stems are spiny. Finally, it is the only plant I know in the western plains and lower mountains with sap that is yellow or orange. If you break a leaf, it bleeds an evil-looking yellow-orange.
It is an annual or biennial, a plant of disturbed sites. So you will see it along the road, or in open sandy spots or next to a prairie dog or gopher burrow.
The spines are quite sharp. This is a plant to look at rather than touch. In addition, the sap is rich in alkaloids that are likely toxic. I can't find much on crested prickly poppy but its relative Mexican prickly poppy, Argemone mexicana, is toxic. (link) I presume both spines and toxins were necessary to protect them from being eaten by large and small animals.
|Dry seed pods of crested prickly poppy|
When the seed pods are open, the plants are dark shapes among the grasses and forbs of the plains and foothills and the seeds in the pods rattle when you bump them. I don't know how many times I have jumped away, looking for the rattlesnake. I have heard real rattlesnakes rattle and it isn't really the same sound. But nevertheless I jump back every time the crested prickly poppy rattles.
This is an attractive native poppy, with relatives all across North America. There is even a prickly poppy native to Hawaii (Argemone glauca) that looks very much like crested prickly poppy. Some places in North America the prickly poppies have yellow or even red flowers. If you see one, stop for a closer look!
Comments and corrections welcome.
Kathy Keeler, A Wandering Botanist
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