Aster family (Asteraceae)
Description: This plant is a spring or summer annual that becomes 4-8" tall. It branches frequently and has a bushy appearance. The slender stems are greyish green from short appressed hairs. The alternate leaves are up to 1" long and less than 1/8" (3 mm.) across, becoming shorter as they ascend the stems. Like the stems, they are greyish green from short appressed hairs. The uppermost leaves are scale-like and insignificant. All of the leaves are linear, smooth along the margins, and sessile.
Each of the numerous upper stems terminates in a small flowerhead about 1/6" (4 mm.) in length. This flowerhead has several pale yellow disk florets, while the surrounding ray florets are purple or absent. When they are present, the ray florets are quite small and insignificant. The cylindrical base of the flowerhead is surrounded by 2 or 3 levels of overlapping linear bracts. These bracts are greyish green, pale purple, or brown. The outer surface of each bract is often covered with short appressed hairs. The blooming period occurs from early summer to early fall and lasts about 1-2 months. There is no noticeable floral scent. Each floret in the flowerhead develops into a light tan achene with a tuft of short white hairs. This achene is linear in shape and lacks a significant beak. As the achenes are released to the wind, the floral bracts spread outward, exposing a naked receptacle (the inner base of the flowerhead to which the achenes are/were attached). The root system consists of a short taproot that branches frequently. This plant spreads by reseeding itself and occasionally forms colonies.
Cultivation: The preference is full sun, dry conditions, and poor soil containing clay, gravel, or sand. This plant tolerates occasional mowing because of its low growth habit. It does not tolerate much competition from taller grasses and forbs.
Range & Habitat: The native Dwarf Fleabane occurs occasionally in scattered areas throughout Illinois. Habitats include dry upland areas of prairies, glades, pastures, abandoned fields, areas along railroads and roadsides, vacant lots with sterile soil, lawns, and miscellaneous waste areas. Dry disturbed areas with scant vegetation are preferred.
Faunal Associations: Little information is available about floral-faunal relationships for this species. The nectar and pollen of the flowerheads probably attract various flies, wasps, and small bees (primarily Halictid bees); these are the insects that usually visit the flowerheads of Conyza canadensis (Horseweed), which have a similar structure and appearance. The bitter-tasting foliage is not attractive to mammalian herbivores.
Photographic Location: A mowed lawn near a grocery store in Urbana, Illinois. This lawn was not far from a railroad.
Comments: Dwarf Fleabane is a rather non-descript little weed that has uninteresting flowers. It stands out from other vegetation by the greyish appearance of its finely branched foliage. The small flowerheads of this species resemble those of Conzya canadensis (Horseweed), except the tiny ray florets of the latter species are white. Horseweed is usually tall (up to 6') and little branched, although dwarf specimens of this species can occur in dry areas with sterile soil. Even a dwarf specimen of Horseweed can be distinguished from Dwarf Fleabane by its greener foliage and the presence of a central stem with spreading white hairs. Dwarf Fleabane has only short appressed hairs and it lacks a central stem.