Spiny herb, which bears the scientific name of Chorizanthe rigida and the alternate common names of devil’s spineflower, rigid spineflower, and rigid spiny-herb, is an annual plant in the Polygonaceae family sometimes referred to as buckwheats. A member of the genus Chorizanthe, the spiny herb is found in the southwestern United States and northwest Mexico, in the states of California, Nevada, Utah, Arizona, Baja California, and Sonora.
Chorizanthe rigida is commonly seen in the Mojave Desert in bajadas, washes and flat mesas that flood with annual rains, and rocky hillsides and ridgelines.
Paradoxically, the plant can be prominent shortly after blooming but is often overlooked as it withers, and it is sometimes hidden under clumps and not seen. On a roadside, its skeleton will be left as a single erect plant, with the taller plants being found in crevices where water pools. In desert flats, the short 3-inch plants are easily obscured by downstream-washed debris that accumulates on the spineflower skeleton. Thus small hillocks of debris are often found with a spineflower in the core. This potentially provides an advantageous form of germinating.
The Chorizanthe rigida plant is short, erect and sometimes single-stalked, but is also multi-stalked to five stalks or more, 2.5–6.0 inches in height. It grows rapidly, in particular after spring rains. With the onset of early summer it turns into a spine-skeleton. It has a main taproot, longer than the plant is tall, taking advantage of the rainfall’s ground moisture.
The devil’s spineflower is an extremely conspicuous bright green when freshly growing. When desiccated, its spiny skeleton is blackish, dark gray, or of medium browns and blends in easily with the desert background ground colors.
For the most part, in the Mojave Desert the rigid spineflower is mostly a 2.5 to 5 inch plant and is often not noticed when the plant goes dry.