Composite Family / Asteraceae or CompositaeAmong the wildwers in the Aleutians there are more species of Compositae than of any other family. They include our most familiar daisylike wers like the abane (Erigeron peregrinus) and Siberian aster (Aster sibiricus), and some of our medicinal plants such as yarrow (Achillea borealis), artemisia (Artemisia spp.), and wild camomile (Matricaria matricarioides). The composites are the second largest family of wering plants and are distributed worldwide. The st step toward identiation of a plant in this large and complex family is to narrow it down to one of three groups. These groups are separated by the types of wering heads. As the name composite implies, what we recognize as wers are actually wering heads composed of many individual wers. These individual wers come in two forms: ray wers and disk wers. Depending on the species at hand, the wering heads may have: (1) both ray and disk wers, (2) only ray wers, or (3) only disk wers. These three choices are the main dividing lines within the family. For example, the abane and Siberian aster, among others, are composed of both. What we commonly call the petals are the rays, or ligules, of the ray wers which radiate from the central disk. The disk is composed of the many crowded tubular or disk wers. Dandelions (Taraxacum spp.) and hawkweeds (Hieracium spp.) have only ray wers and lack a central disk. Artemisia (Artemisia spp.) and pearly everlasting (Anaphalis margaritacea) have only disk wers, although the surrounding bracts sometimes look like rays. To narrow a plant down further to its genus, look for other distinctions such as the color of the rays, whether the wering heads are solitary or many, and whether the leaves are opposite or alternate, divided or simple. Identiation at the species level sometimes requires a hand lens, a keen knowledge of the wer parts, and a new vocabulary of descriptive terms. This is the best way to learn the identiation of these plants but requires time and patience. While more than two dozen species of Compositae have been recorded in the islands, not all of them extend throughout the chain. Asters are found only in the eastern islands. Arctic daisies (Chrysanthemum arcticum) grow in the western and central islands, and the Kamchatka thistle (Cirsium kamtschaticum) has been recorded only in the westernmost Aleutian Islands.183 Composite Family / Asteraceae or Compositae
