This is the largest and youngest of all the flower families. It is so named because each "flower" is really a composite of many smaller flowers. The typical composite is radially symmetrical and has tiny tubular flowers in a central disc, surrounded by flat ray flowers. There is no calyx, and either disc or ray flowers may be absent. The flowers are supported by small leaflets or "bracts". The leaves may be alternate, opposite, or whorled, and may be simple or compound. The seeds may have bristles or soft hairs to aid in their dispersal.

As an aid to identification, the composites have been arranged in nine sub-groups: Aster like, sunflower-like, dandelion-like, the goldenrods, the lettuces, Joe-Pye-weed-like, thistle-like, no obvious symmetry and miscellaneous.

Aster-Like

The asters are mostly perennial plants. The leaves are alternate and the flowers are always white or bluish, never yellow or red. The discs are yellow but may turn color as they mature. Bloom late summer and fall.

A few species not in the Aster genus, such as the fleabanes and ox-eye daisy, are included in this group, since they have yellow discs and white rays and therefore superficially resemble the asters.

Dandelion-Like

Plants in the Dandelion-like group are usually smaller and have smaller flowers than those in the Sunflower group; most often less than 2'' tall and flowers rarely more than 1" wide. Leaves are often in a basal rosette. Often there are only ray flowers, but some species have only disc flowers, others have both ray and disc flowers. Always, though, the flowers are yellow.

See also the Sunflower-Like group, since in some species, the height and flower size of individual plants may fit into either group.

E Miscellaneous

Species in the Composite Family that do not fit into any of the other subgroups in this family.

Goldenrod

Goldenrods have tiny yellow flowers variously arranged in plumes, wands, or flat-topped clusters. Bloom late summer and fall. Identification of the individual species is often difficult.

Joe-Pye-Weed-Like

The Eupatoriums, or Thoroughworts, exemplified by the Joe-Pye-weeds, have small flower heads borne in large clusters. There are no rays, only disc flowers, often with protruding stamens that give the flowers a fuzzy appearance. The usually toothed leaves are most often whorled or opposite.

Lettuce

The lettuces include the Lactuca and Prenanthes genera.

The Lactucas are usually quite tall but have small flowers made up only of square-tipped, 5-toothed rays (actually 5 fused rays). The flowers are blue, yellow or white. As the genus name implies, the sap is milky white.

The Prenanthes are smaller plants and have clusters of small, dangling cylindrical flowers. Only the tips of the ray flowers protrude from their encasing cylinder of bracts. The sap is also milky. Some Prenanthes roots were once used as a remedy for snakebite, hence the alternate name "Rattlesnake root".

No Obvious Symmetry

Species in the Composite Family with flowers displaying no obvious symmetry.

Sunflower-Like

Plants in the sunflower-like group are relatively large, most are at least 2 1/2'' tall. The flowers are also large, almost always 1" or more in diameter, and are always yellow. All have both disc and ray flowers.

The dandelion-like group plants also have yellow flowers, but both the plants and the flowers tend to be smaller. Most have only ray flowers, but a few have only disc flowers, or both disc and ray flowers.

Thistle-Like

The stems of thistles are sometimes prickly, but may be hairy or even smooth. The flower heads have no rays, only disc flowers. The bracts are often, but not always tipped with sharp spines.

Burdock is not a thistle, but is included here because of its prickly burs.