Aster family (Asteraceae)
Description: This introduced perennial plant consists of a rosette of basal leaves and occasional flowering stalks. The basal leaves are individually up to 10" long and 2½" across. The typical basal leaf is broader toward its outer tip than at the base (oblanceolate) in outline, although it is more or less lobed (pinnatifid) along its length. These lobes are triangular. The margins are slightly wavy and irregular, and sometimes coarsely dentate. There is a prominent central vein along the length of each leaf that is hollow and contains milky juice. This vein is usually green, but it sometimes becomes reddish green toward the base. The leaves are usually hairless, although young leaves are sometimes slightly pubescent. From the center of the rosette, one or more flowering stalks are produced that are up to 18" tall, although usually 12" or less. Each slender stalk is round and hollow, and contains milky juice. It is usually light green, sometimes becoming light reddish green toward the base. There may be some appressed cobwebby hairs along its length. At the apex of each flowering stalk, there is a single yellow flowerhead about 1-2" across.
This flowerhead has about 150-200 yellow ray florets and no disk florets; the ray florets spread outward from the center. At the base of the flowerhead, there are inner and outer bracts that are green. The inner bracts are linear or linear-lanceolate and appressed together to form a cylindrical tube around the ovaries of the flowerhead. The outer bracts are linear-lanceolate and sharply curve downward. The flowerheads are produced sporadically from early spring to late fall; they are most like to occur during the late spring or early summer. There is a pleasant floral scent that is somewhat musty and pollen-laden. Each ray floret produces a single slender achene that is light brown, light gray, or slightly olive green. An achene has 5-10 longitudinal ribs with tiny teeth toward its apex. A long slender beak connects the achene with a tuft of white hairs. This beak is 2-3 times as long as the achene. Collectively, these tufts of hair produce a spheroid mass that is white and feathery in appearance. The achenes are dispersed by the wind. The root system consists of a stout taproot that is up to 3' long (if not more). This taproot contains milky juice and is somewhat fleshy. This plant spreads by reseeding itself. It can form large colonies.
Cultivation: The preference is full sunlight, mesic conditions, and a soil that consists of loam or clay-loam. Partial sunlight is also tolerated. This plant can be very aggressive, and can regenerate from small pieces of the taproot.
Range & Habitat: Dandelion is a very common plant that occurs in every county of Illinois (see Distribution Map). It was introduced to North America from Europe. Habitats include lawns, gardens, degraded meadows, vacant lots, and sunny areas along roads and railroads. Dandelion has little capacity to invade high quality natural habitats, always preferring open areas that are disturbed and degraded by human-related activities.
Faunal Associations: The nectar or pollen of the flowers primarily attracts long-tongued bees, short-tongued bees, and bee flies. Among the bees, are such visitors as bumblebees, honeybees, Mason bees, Halictid bees, and Andrenid bees. The foliage of Dandelion is eaten by many kinds of insects, including the caterpillars of several species of moths (see Moth Table). Most of these moths are polyphagous, as their caterpillars will feed on a variety of low-growing plants. In the Eastern states and the Midwest, only the Goldfinch and the English Sparrow eat the seeds to any significant extent. While the foliage is somewhat bitter, it is eaten occasionally by various mammalian herbivores, including livestock, rabbits, groundhogs, and deer.
Photographic Location: At the apartment complex of the webmaster in Urbana, Illinois.
Comments: The young leaves of Dandelion are sometimes used fresh in salads, or boiled as a potherb. When the flowerheads develop, the foliage becomes increasingly bitter and tough. The leaves are high in vitamins and minerals. Sometimes the flowerheads are used to make dandelion wine. Most people regard Dandelion as a pernicious weed (with some justification), even though the flowers are quite attractive. Because it can bloom very early or very late in the year, the nectar or pollen of the flowerheads are a valuable source of food to some pollinating insects, especially bees. There are many members of the Aster family that produce a rosette of leaves with stalks of flowerheads that consist entirely of yellow ray florets. As a result, people sometimes confuse other species in this group with Dandelion. Dandelion has the following characteristics that may be useful in making a correct identification: 1) the outer green bracts curve sharply downward from the flowerheads, 2) only a single flowerhead is produced from a hollow flowering stalk, and 3) the outermost lobe of each leaf is the largest. There is also another dandelion species, Taraxacum erythrospermum (Red-Seeded Dandelion) that sometimes occurs in Illinois. This species has achenes that are reddish brown and its leaves are more deeply pinnatifid than the typical Dandelion. Also, the slender beak connecting the achene with its tuft of hair is shorter (up to twice the length of the achene) in this species than the beak of the typical Dandelion (2-3 times as long as the achene).