Asteraceae

Flower diagram of Carduus (Carduoideae) shows (outermost to innermost): subtending bract and stem axis; fused calyx; fused corolla; stamens fused to corolla; gynoecium with two carpels and one locule

A typical Asteraceae flower head (here Bidens torta) showing the individual flowers

Ray floret (as in Cichorioideae, and the outer florets in Asteroideae). A = ovary, B = pappus, C = anthers, D = ligule, E = style with stigmas

Asteraceae or Compositae (commonly referred to as the aster, daisy, composite, or sunflower family) is an exceedingly large and widespread family of flowering plants (Angiospermae).

The family has more than 23,600 currently accepted species, spread across 1,620 genera (list) and 13 subfamilies. In terms of numbers of species, the Asteraceae are rivaled only by the Orchidaceae. (Which of the two families is actually larger is unclear, owing to uncertainty about exactly how many species exist in each family.) Many members have composite flowers in the form of flower heads (capitula or pseudanthia) surrounded by involucral bracts. When viewed from a distance, each capitulum may have the appearance of being a single flower. The name "Asteraceae" comes from the type genus Aster, from the Greek ἀστήρ, meaning star, and refers to the star-like form of the inflorescence. "Compositae" is an older but still valid name which refers to the fact that the family is one of the few angiosperm ones to have composite flowers.

单词	Discoid head
释义	Discoid head 英语百科 Asteraceae Asteraceae or Compositae (commonly referred to as the aster, daisy, composite, or sunflower family) is an exceedingly large and widespread family of flowering plants (Angiospermae). The family has more than 23,600 currently accepted species, spread across 1,620 genera (list) and 13 subfamilies. In terms of numbers of species, the Asteraceae are rivaled only by the Orchidaceae. (Which of the two families is actually larger is unclear, owing to uncertainty about exactly how many species exist in each family.) Many members have composite flowers in the form of flower heads (capitula or pseudanthia) surrounded by involucral bracts. When viewed from a distance, each capitulum may have the appearance of being a single flower. The name "Asteraceae" comes from the type genus Aster, from the Greek ἀστήρ, meaning star, and refers to the star-like form of the inflorescence. "Compositae" is an older but still valid name which refers to the fact that the family is one of the few angiosperm ones to have composite flowers.
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Discoid head

Asteraceae