Hobbies And Interests
Flowers
The defining characteristic of this family is found in the flower head, the capitulum. Asteraceae florets come in three varieties: disc, ray or ligulate. Ray florets project out from the disc in a "ray," as easily observed on sunflowers. Disc florets are directly on the disc, at the center of the flower head. Ligulate florets form a tube. Flowers have a large receptacle with bracts, which are seed bearing structures. Flowers are radiate, a mix of disc and ray florets; discoid, only disc florets; or ligulate, only ligulate florets. The ovary of each flower is epigynous, located below the corolla and stamen.
Leaves, Stems and Roots
Asteraceae leaves are alternate, opposite or sometimes whorled. Many species' leaves are undivided and spoon-shaped. Some are prickly, others smooth. The stem may be hollow or solid, and can be thorny or smooth. Some stems have leaves, as found in thistle. Roots can be short and superficial, as in daisies, or long taproots, as in dandelions.
Seeds
Asteraceae flowers are on discs surrounded by bracts. In many species the seeds are dispersed by wind when the bracts open. In some species, like the dandelion, seeds have "parachutes," which aid in their dispersal. Seeds are usually oval, but some are round or flat. They can be brown, straw-colored or nearly black.
Geography
Asteraceae are cosmopolitan: they are found throughout the world. They are most common in mountainous regions of the tropics and subtropics, in semiarid climates and in Mediterranean climates.
Some Genera
Some of the most common genera include Genus Helianthus, sunflowers; Genus Cirsium, thistle; Genus Tagetes, marigolds; Genus Malacothrix, desert dandelions; Genus Leucanthemum, daisies; Genus Anthemus, chamomile; Genus Cynara, artichoke; Genus Monoptilon, desert star; Genus Solidago, goldenrod; Genus Leontopodium, edelweiss; and Genus Stephanomeria, wreath plant.