Rosidae: Celastrales. The Celastraceae are trees and shrubs comprising about 50 genera and 800 species that are sometimes climbing or vining. The leaves are simple and alternate or opposite; stipules are small and caducous or absent. The flowers are bisexual or sometimes functionally unisexual, actinomorphic, and are small and often greenish. The calyx comprises 4 or 5 usually basally connate sepals. The corolla is rarely absent or more commonly consists of 4 or 5 distinct petals. The androecium consists of 4 or 5 or rarely 10 distinct stamens that alternate with the petals. The gynoecium is a single compound pistil of 2-5 carpels, a single short style, and a superior or rarely half inferior ovary with 2-5 locules, each containing usually 2 axile ovules. An annular nectary disk surrounds and is usually adnate to the ovary. The fruit is a capsule, berry, samara, or drupe.
Each "thumbnail" image below is linked to a larger photograph.
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Celastrus sp. Note greenish, 4-parted flowers with conspicuous nectary disk and alternate stamens. |
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Elaeodendron orientale. In this species the ovary is completely buried in the nectary disk. The developing fruit in the background clearly reveals the superior nature of the ovary. |
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Catha sp. In this species the annular nectary disk is visible as a light greenish ring around the darker green ovary. The alternate stamens arise from just outside the disk. The flowers in the lower right exhibit 3-lobed stigmas and indicate the 3-carpellate nature of the gynoecium in this example. |
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Perrottetia sandwicensis, olomea. The flowers of this Hawaiian native member of the family are reddish but are still very small. The disk is visible as a yellow ring around the emergent style. |