Annual or perennial herbs with radical and alternate or spiral leaves (Knowltonia, Ranunculus and Thalictrum), or shrublets or woody climbers with opposite or whorled leaves (Clematis (including Clematopsis)). Stipules present or 0. Leaves simple or compound. Inflorescences usually terminal and 1-many-flowered. Flowers hypogynous, usually bisexual and actinomorphic; sometimes polygamous or dioecious. Sepals free, often petaloid. Petals free, sometimes 0. Stamens numerous. Carpels 1-many, usually free. Fruit usually composed of 1 or more follicles or a cluster of achenes.
Barcode of Life Data Systems (BOLD) Stats Specimen Records:3318 Specimens with Sequences:4099 Specimens with Barcodes:2581 Species:947 Species With Barcodes:932 Public Records:2408 Public Species:838 Public BINs:0
Flower diagram of Adonis autumnalis from Strasburger et al. 1900
Most members of the family have bisexual flowers which can be showy or inconspicuous, and can be radially or bilaterally symmetrical. The sepals and petals are generally free (unfused) and typically number four or five. In many species, the sepals are colorful and appear petal-like. In these species, the petals can be inconspicuous or absent. The stems are unarmed. The leaves are variable. Most species have both basal and cauline (stem) leaves, which are usually compound or lobed but can be simple. They are typically alternate, or occasionally opposite or even whorled. Many species, especially the perennials form rhizomes that develop new roots each year.
According to Dr John David, (2010) the Ranuculaceae are combined with the Eupteleaceae, Lardizabalaceae, Menispermaceae, Berberidaceae, and Papaveraceae in the Ranunculales, the only order in the superorder Ranunculanae. This follows the work of the Angiosperm Phylogeny Group.
Takhtajan 1997 includes the Ranunculaceae as the only family in the Ranunculales which he placed in a subclass, the Ranunculidae, instead of a superorder. Previously, Thorn 1992 placed the Ranunculaceae in the Berberidales, an order within the Superorder Magnolianae. Earlier Cronquist in 1981 included the Ranunculaceae along with seven other families in the Rancunculales which was included in the Magnoliidae, which he regarded as a subclass.
The cladogram below is according to the APG II system, based on molecular phylogeny.
The genus Glaucidium was once put in its own family (Glaucidiaceae), but has been recently recognised as a primitive member of Ranunculaceae. Tamura (1993) recognised five subfamilies, mainly based on chromosomic and floral characteristics (Hydrastidoideae, Thalictroideae, Isopyroideae, Ranunculoideae, Helleboroideae).
Fossils of fruits, pollen, seeds, and leaves are known from several dozen locations. The fossil record begins in the early Cretaceous and continues throughout the Tertiary. In most cases, the fossils are assigned to extant genera, or show a close relationship to a particular extant genus.
^ abKathleen B. Pigg and Melanie L. DeVore (2005), "Paleoactaea gen. nov. (Ranunculaceae) fruits from the Paleogene of North Dakota and the London Clay", American Journal of Botany 92: 1650–1659, doi:10.3732/ajb.92.10.1650
Tamura, M.: "Ranunculaceae.", en Kubitzki, K., Rohwer, J.G. & Bittrich, V. (Editores). The Families and Genera of Vascular Plants. II. Flowering Plants - Dicotyledons..- Springer-Verlag: Berlín, 1993.- ISBN 3-540-55509-9
Strasburger, Noll, Schenck, Schimper: Lehrbuch der Botanik für Hochschulen. 4. Auflage, Gustav Fischer, Jena 1900, p. 459 (flower diagrams)