Ranunculaceae

Magnoliidae: Ranunculales: The Ranunculaceae are herbs or rarely shrubs or vines comprising 50 genera and 2,000 species. The leaves are typically alternate, compound, and stipulate. The flowers are actinomorphic or less commonly zygomorphic and are usually bisexual. The perianth is usually in two, often 5-merous cycles that may or may not be differentiated into calyx and corolla. The petals are usually nectariferous near the base, and in Ranunculus there is a flap of tissue in this position. Typical flowers have many helically disposed stamens and simple pistils on an elongated receptacle. All of the floral parts are distinct. Each pistil has a superior ovary with one locule and 1-several parietal ovules. A single flower commonly produces a cluster of achenes or follicles.

Each "thumbnail" image below is linked to a larger photograph.

	Ranunculus sp., buttercup. Note the flower with many yellow stamens that are partly obscuring the numerous pistils in the center of the flower. The extra petal shows the basal flap of tissue associated with the nectariferous pit.
	Ranunculus sp., buttercup. This rather mature flower with most of the floral parts removed shows a cluster of achenes developing from the pistils.
	Ranunculus hawaiensis, makou, buttercup. Hawaiian endemic.
	Helleborus orientalis. On the right is a typical flower at anthesis. On the left an older flower that has lost its stamens exhibits a cluster of developing follicles.
	Caltha leptosepala, marsh marigold.
	Anemone hupehensis var. japonica, Japanese windflower. Note many stamens and very numerous, tightly packed pistils in center of flower.
	Clematis tangutica. This is an example of a vining member of the buttercup family with a single cycle of perianth consisting of a 4-merous petaloid calyx. Note the many stamens and large number of pistils. As visible in the background, the styles elongate and become feathery, acting to increase dispersibility of the achenes.
	Thalictrum sp., meadow rue. This is rare example of the family with unisexual, wind pollinated flowers.
	Nigella damascena. This genus is exceptional in the buttercup family for its syncarpous, capsular fruit.

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