Bastard Toadflax

Comandra umbellata

The common epithet, bastard toadflax, while colorful, may mislead; neither the flower nor leaves resemble a flax or a toadflax. Toadflax, a common name given to several plants in the Scrophulariaceae family, received its name because the flowers "be yellow, having a mouth unto a frog’s mouth," according to John Gerard’s 1597 Herbal, although 60 years later another English botanist, William Coles, in his Adam in Eden, Or the Paradise of Plants, claimed the name arose "because Toads will sometimes shelter themselves amongst the branches of it." Bastard means false or of unusual shape or size. Comandra comes from the Greek Kome (hair) and aner (man), referring to the hairs superficially attached to the base of the anthers. Umbelatta alludes to the flat-topped flower clusters.

Bastard Toadflax


Perennial, 4 to 15-inch-tall erect plants. The simple, alternate leaves are smooth and linear or lance-shaped. In the fall, when plants lack leaves, they look like a typical stick. The small (less than _ inch) white flowers, which bloom in the spring, lack petals; instead, the five sepals are white. Blossoms remain open night and day for two days. The minute fruit are drupes, that is, they have a soft fleshy part around the seed stone. They generally drop from the plant while still greenish, soft and leathery. Henry David Thoreau called it a "handsome" plant.


The plant prefers rather dry, partly to completely open sites and often grows in roadcuts and similar clearings. It also occurs in sandy areas, along riparian corridors, in hanging gardens, and the pinyon-juniper woodlands.

As a parasite, the bastard toadflax depends upon other plants for survival. Within two weeks of seed germination, subterranean connections, known as haustoria, attach themselves to nearby vegetation to obtain nutrients and water. Haustoria range in width from two to four millimeters, with smaller clasping ones wrapping around the host, while larger bulb-shaped ones butt up against the host. One product obtained during parasitism is water, which may help explain how bastard toadflax can survive in dry sites with porous soils.

Comandra parasitizes over 200 woody and herbaceous species, the most diverse and largest natural range of any parasitic plant. Although it is always parasitic, it can also make its own food through photosynthesis; therefore some botanists consider it to be a semi-parasite.

Bastard toadflax reproduces both sexually and vegetatively. Sexual reproduction is less common, but more important for dispersal over greater areas. During vegetative spreading, plants send out numerous shoots or ramets, and a single clone may cover up to 90 square yards. This type of reproduction is especially important in shady areas and helps the plant accumulate food reserves for sexual reproduction.


Bastard toadflax grows across the United States and north into Canada. Herbarium specimens have also been collected in the Balkan region of Turkey, Bulgaria, Rumania and the former Yugoslavia. These unusual populations may be relicts that survived the last ice age, indicating that Comandra umbelatta once had a much greater distribution, or they may be from plants introduced from North America.


Ironically, bastard toadflax is also parasitized by a pathogenic microorganism, known as the comandra-pine blister rust fungus. These rusts produce five types of spores, three of which occur on bastard toadflax. An infected Comandra will have yellow blister-like spots on the leaves. After passing through two additional spore cycles, the rust will transfer to pines via wind. The rust fungus causes growth reduction, stem deformity and mortality. In addition, pines with stem cankers produce significantly fewer cones and seeds than healthy trees.

David B. Williams


Share this page on Facebook:

DesertUSA Newsletter -- We send articles on hiking, camping and places to explore, as well as animals, wildflower reports, plant information and much more. Sign up below or read more about the DesertUSA newsletter here. (It's Free.)

The Desert Environment
The North American Deserts
Desert Geological Terms


Enter Email:

Shop desert store



Hot temperatures in the desertAre you interested in the temperatures in the desert?

Click here to see current desert temperatures!

Copyright © 1996- and Digital West Media, Inc. - -