Asteridae: Rubiales. The Rubiaceae are trees, shrubs, or infrequently herbs comprising about 450 genera and 6,500 species, including some lianous forms. The leaves are simple and usually entire, and are opposite or sometimes whorled; stipules are present and interpetiolar. The flowers are nearly always bisexual and actinomorphic, often heterostylous, and usually are in cymose inflorescences. The calyx is mostly somewhat reduced and 4-5-lobed or sometimes the lobes are obsolete or rarely one of them greatly expanded and brightly colored. The sympetalous corolla is mostly 4-5-lobed, occasionally with 3 or up to 10 lobes. The androecium consists of as many stamens as corolla lobes and is adnate to the corolla tube or epigynous zone, alternate with the lobes. The gynoecium consists of a single compound pistil of 2 or seldom more carpels, a single style, and a nearly always inferior ovary with the number of locules equaling the number of carpels, each with 1-many axile ovules. An epigynous nectary disk is usually present. The fruit is variable, sometimes forming multiples.
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