Dwarf Snapdragon
Chaenorrhinum minus
Figwort family (Scrophulariaceae)

Description: This adventive annual plant is about 4-12" tall, branching occasionally. The narrow round stems are covered with white hairs. The lower leaves are opposite, while the middle to upper leaves are alternate. These leaves are up to 1" long and 1/6" across. They are linear-oblong or linear-oblanceolate, with margins that are ciliate and smooth. From the axil of each middle or upper leaf, a single flower develops from a slender pedicel about 1" long. Sometimes a second flower develops from the leaf axil. Like the stems, these pedicels are covered with white hairs. The flowers are up to 1/4" in length. The corolla is tubular, with 5 spreading lobes in the front and a short spur in the back. The corolla has a small opening at the throat and is more or less two-lipped with 2 upper lobes and 3 lower lobes. It is variously colored, usually some shade of lavender, light purple, or white. Sometimes the corolla is bicolored, with the upper lobes lavender or light purple and the lower lobes white. There are usually a few hairs at the base of the lower lobes. The calyx is green or purplish green and quite hairy. It has 5 oblanceolate lobes that are almost as long as the corolla. 

The blooming period occurs during the summer and lasts about a month. There is no noticeable floral scent. Each flower is replaced by an ovoid capsule that contains numerous brown seeds. These seeds are tiny enough to be dispersed by gusts of wind. The root system consists of a slender taproot. This plant spreads by reseeding itself.

Cultivation: This little plant prefers dry sunny conditions and a sterile soil that is sandy or gravelly. It also grows in partial sun and less dry conditions, in which case it will become somewhat taller and more leafy. In fertile soil, this plant is not competitive with taller vegetation. Alkaline soil is readily tolerated.

Range & Habitat: Dwarf Snapdragon has been reported from most counties in Illinois (see Distribution Map). It is occasional to locally common. Habitats include gravelly areas along railroads (including the ballast), sandy or gravelly areas along roads, gravelly borders along buildings, and sterile waste areas. Disturbed areas are preferred. Dwarf Snapdragon is especially common along railroads in part because the wind gusts produced by passing trains help to disperse the tiny seeds. This plant is adventive from the Mediterranean area of Europe. It is less common along railroad tracks than formerly because of the application of herbicides.

Faunal Association: Little information is available about floral-faunal relationships. The flowers are pollinated by small bees, although they are also capable of self-pollination. The seeds are too small to be of any interest to birds, and the insubstantial foliage is unlikely to provide much nourishment to mammalian herbivores. Humans assist in the dispersal of the seeds of this plant because of their passing trains and motor vehicles, as noted above.

Photographic Location: A border along a building that was filled with pebbles. This building was located along a railroad in Urbana, Illinois. The flower in the upper photograph is bicolored.

Comments: Sometimes this plant is called "Small Snapdragon" and "Lesser Toadflax." It resembles the Linaria spp. (Toadflaxes) somewhat, except the throat of the corolla is less obstructed by fuzzy hairs and a palate covers the lower lip. Dwarf Snapdragon is one of the members of a group of plants that colonize disturbed sterile soil; these species are ecologically significant because they help to stabilize and restore the fertility of the soil. An alternative spelling of the scientific name for this plant is Chaenorhinum minus.

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