Family: Asteraceae; Compositae
Common name: sunflower family [Zomlefer, pp. 203-211]
Diversity: Worldwide: 1,100 genera; 19,000 species
U.S.: >200 genera
PNW (Hitchcock & Cronquist): 104 genera
second largest family;
subdivided into 2 subfamilies and 12 to 17 tribes
Flower -- Vegetative Features -- Economic Importance -- Flower Images-- Web Sites

Kx Co(5) S or 0 P or 0
Sexuality: bisexual or unisexual
Symmetry: actinomorphic and zygomorphic
Inflorescence: flowers (florets) in a head (=capitulum); heads in racemes, panicles, corymbs or compound heads
Calyx (sepals): rudimentary or absent (called a pappus)
Corolla (petals): 5, united petals forming a tube. actinomorphic in "disc/tube" florets, often with five lobes at their tips;
zygomorphic in "ray/ligulate" florets
Androecium: 5 stamens, united by their anthers forming a tube around the style
Gynoecium: 2 united carpels, inferior ovary (=epigynous), single style with two stigmatic lobes, single ovule
Fruit: achenes or cypsela (=achene with attached calyx)
Other features: head is composed of tiny florets, surrounded below by 1 to several series (=involucre) of protective bracts

some heads with bisexual, ray florets only; some heads with bisexual, tube florets only; some heads with outer ray and central tube florets

derived breeding systems include dioecy, monoecy (ray=female/disc=male) and gynomonoecy (ray=female/disc=bisexual)

Vegetative Features
watery or milky sap
Leaves: usu. alternate, rarely whorled, often basal rosette, simple, rarely compound, exstipulate
Life-history: annual to perennial
Habit: mostly herbs and shrubs or trees
Distribution & Ecology: cosmopolitan
infrequent in tropical rain forest
Some Northwest Genera: Antennaria, pussytoes
Arnica, arnica
Artemesia, wormwood, sagebrush
Aster. aster
Balsamorhiza, balsam root
Centaurea, knapweed
Cirsium, thistle
Crepis, hawksbeard
Erigeron, fleabane
Haplopappus, goldenweed
Helianthus, sunflower
Hieracium, hawkweed
Madia, tarweed
Microseris, microseris
Senecio, ragwort
Solidago, goldenrod

Economic Importance
limited direct economic importance
Crops: Carthamus, safflower oil
Lactuca lettuce
Cynara, artichoke
Helianthus, sunflower
Ornamentals: many garden ornamentals (e.g.Chrysanthemum, Dahlia, and Zinnia)
Weedy and pest species: Taraxacum, dandelion
Cirsium, thistle
Senecio jacobaea, tansy ragwort
Xantium, cocklebur
Ambrosia, ragweed (hayfever contributor)

Examples Compositae Balsamorhiza
Compositae Centaurea
Compositae Cichorium
Compositae Cirsium
Compositae Taraxacum
click on the genus name for a flower image

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