Asteridae: Gentianales. The Apocynaceae are trees, shrubs or sometimes herbs, usually with milky sap comprising about 200 genera and 2,000 species. The leaves are simple, usually opposite and decussate, or whorled; stipules are usually absent. The flowers are bisexual and actinomorphic or sometimes weakly zygomorphic. The calyx is synsepalous and usually 5-lobed. The corolla is sympetalous and usually 5-lobed. The stamens are distinct, as many as corolla lobes and alternate with them, and adnate to the corolla tube (or perigynous zone). The anthers are introrse and commonly adherent to the surface of the stigma. The gynoecium consists of a single compound pistil of 2 carpels that may be distinct at the level of the superior or rarely partly inferior ovary but which are united by a single style. When distinct, each ovary typically has few to numerous ovules on marginal placentae; when connate, the placentation is axile or intruded parietal. A nectary consisting of 5 glands or an annular ring is usually found at the base of the ovary. The fruit is commonly a follicle, capsule, or berry. The seeds usually are flat and winged or have a tuft of hairs at one end.
Each "thumbnail" image below is linked to a larger photograph.
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Beaumontia jerdoniana. This species has a very broad corolla tube which makes it possible to easily see the anthers adhering to the stigma. |
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Carissa macrocarpa, Natal plum. In this species the tube of the 5-lobed corolla is very narrow. Note the paired red fruits that have developed from the separate ovaries of the single pistil. They diverged during the maturation period following abscission of the unifying style. |
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Plumeria obtusa, Singapore plumeria. This is one of the very common lei flowers in Hawaii. |
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Nerium oleander, oleander. This is a highly poisonous member of the family. The flowers have a fringe of extra appendages in the throat of the corolla. |
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Cerbera manghas. Note the white sap oozing from the cuts on the fruit. Sap from species such as this have been used in arrow poisons. |
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Cascabela thevetia, be-still tree. This is another example of a poisonous member of the family. Note the small droplets of white sap seeping out of the lower half of the fruit. |
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Stemmadenia littoralis, lecheso. Note the complete separation of the two carpels in the developing fruit on the right (it originated from the bicarpellate gynoecium of a single flower such as that on the left). |
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Alyxia oliviformis, maile. The bark and leaves of this native Hawaiian vine are used to make a fragrant lei. |