The Families of Angiosperms

L. Watson and M.J. Dallwitz

Ranunculaceae Juss.

Including Coptaceae (Gregory) Löve & Löve, Helleboraceae von Vest, Nigellaceae J.G. Agardh, Thalictraceae Rafin.; excluding Glaucidiaceae, Hydrastidaceae, Kingdoniaceae.

Habit and leaf form. Herbs (mostly), or shrubs (Xanthorhiza), or lianas (Clematis); non-laticiferous, without coloured juice; without essential oils. Annual to perennial; with a basal aggregation of leaves, or without conspicuous aggregations of leaves; often rhizomatous (or stoloniferous), or tuberous. Self supporting, or climbing. Hydrophytic to mesophytic; when hydrophytic, rooted. Leaves of aquatics emergent, or submerged, or submerged and floating. Conspicuously heterophyllous (commonly, when hydrophytic), or not conspicuously heterophyllous. Leaves alternate (usually), or opposite (Clematis); usually spiral; petiolate; sheathing. Leaf sheaths with free margins. Leaves not gland-dotted; without marked odour, or foetid; simple, or compound; peltate (more or less, occasionally), or not peltate; epulvinate; when compound pinnate, or palmate, or bipinnate, or multiply compound. Lamina when simple dissected, or entire; when simple/dissected palmatifid, or much-divided; pinnately veined, or palmately veined; cross-venulate (usually), or without cross-venules. Leaves stipulate (commonly rather conspicuously so), or exstipulate. Stipules intrapetiolar. Lamina margins entire, or crenate, or serrate, or dentate. Leaf development not ‘graminaceous’.

Leaf anatomy. Hydathodes present (occasionally), or absent. Minor leaf veins without phloem transfer cells (Helleborus, Ranunculus).

Axial (stem, wood) anatomy. Young stems with solid internodes, or with hollow internodes. Pith homogeneous, or heterogeneous. Cork cambium present, or absent. Nodes unilacunar (rarely), or tri-lacunar to multilacunar. Primary vascular tissues comprising a ring of bundles, or comprising two or more rings of bundles, or consisting of scattered bundles; collateral. Secondary thickening absent (commonly), or developing from a conventional cambial ring.

The vessels in Clematis, clustered, or in tangential arcs. The vessel end-walls simple (at least usually). The axial xylem with fibre tracheids; with libriform fibres, or without libriform fibres. The wood partially storied (VP), or not storied.

Reproductive type, pollination. Unisexual flowers present, or absent (usually). Plants hermaphrodite, or dioecious (rarely, by suppression). Floral nectaries present (usually), or absent (e.g. Anemone, Clematis, Thalictrum). Nectar secretion from the perianth, or from the androecium (from the bases of the petals, considered staminodial in origin). Pollination entomophilous (usually — attracting insects by either nectar or pollen), or anemophilous (e.g. Thalictrum).

Inflorescence, floral, fruit and seed morphology. Flowers solitary (often pedunculate), or aggregated in ‘inflorescences’; in cymes, or in racemes, or in panicles. The ultimate inflorescence units cymose. Inflorescences scapiflorous, or not scapiflorous; terminal, or axillary; various, but determinate. Flowers small to medium-sized; regular (usually), or somewhat irregular to very irregular (Aconitum etc.); cyclic (Aquilegia), or partially acyclic, or acyclic. When more or less acyclic the perianth acyclic, the androecium acyclic, and the gynoecium acyclic, or the androecium acyclic and the gynoecium acyclic, or the gynoecium acyclic. Floral receptacle not markedly hollowed (convex or elongated). Free hypanthium absent. Hypogynous disk absent.

Perianth with distinct calyx and corolla, or sequentially intergrading from sepals to petals, or sepaline, or petaline; 5–50 (to ‘many’); free, or joined. Calyx when definable (3–)5–8 (or more, often becoming petaloid); polysepalous, or partially gamosepalous, or gamosepalous; basally spurred, or neither appendaged nor spurred; persistent, or not persistent; imbricate, or valvate. Corolla when definable 3–50 (to ‘many’ — perhaps staminodal in origin); polypetalous, or partially gamopetalous, or gamopetalous; imbricate; green, or white, or yellow, or red (e.g. some Aquilegia species), or purple, or blue; spurred (occasionally), or not spurred (or with little tubular nectariferous ‘petals’). Petals clawed, or sessile.

Androecium 15–100 (usually ‘many’). Androecial members unbranched; maturing centripetally; free of the perianth; free of one another; 1–13 whorled (or spiralled). Androecium including staminodes (usually several or many, if nectaries of various kinds between perianth and stamens are interpreted as such), or exclusively of fertile stamens. Staminodes external to the fertile stamens; petaloid, or non-petaloid. Stamens (5–)10–100 (usually ‘many’). Anthers adnate; non-versatile; dehiscing via longitudinal slits, or dehiscing by longitudinal valves (e.g. Trautvetteria); extrorse, or latrorse; tetrasporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with one middle layer, or initially with more than one middle layer (1 or 2); of the ‘dicot’ type. Tapetum glandular. Pollen grains aperturate (usually), or nonaperturate (Souliea); (2–)3 aperturate; variously colpate, or foraminate, or rugate, or spiraperturate (but not colporate, not even colporoidate); 2-celled (recorded in 9 genera).

Gynoecium (1–)3–100 carpelled (i.e. to ‘many’). The pistil when other than apocarpous, 1 celled, or 3–5 celled. Gynoecium monomerous, or apocarpous, or syncarpous; of one carpel (Actaea), or eu-apocarpous (nearly always), or semicarpous (carpels sometimes more or less connate, e.g. Aquilegia), or synovarious (e.g. Nigella); superior. Carpel non-stylate, or stylate; apically stigmatic; (when monomeric or apocarpous) 1 ovuled, or 2–100 ovuled (‘several to many’). Placentation when monomeric or apocarpous marginal, or basal. Ovary when syncarpous, 3–5 locular. Styles when syncarpous, 3–5; apical. Stigmas dry type; papillate, or non-papillate; Group II type. Placentation when syncarpous, axile. Ovules when syncarpous, 3–15 per locule (?); pendulous, or horizontal, or ascending; with ventral raphe to with dorsal raphe; non-arillate; hemianatropous, or anatropous; unitegmic, or bitegmic; crassinucellate (when bitegmic), or pseudocrassinucellate (when unitegmic). Embryo-sac development Polygonum-type, or Allium-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3 (sometimes multinucleate); proliferating (rarely), or not proliferating. Synergids pear-shaped, or hooked (sometimes with filiform apparatus). Endosperm formation nuclear. Embryogeny onagrad (or undifferentiated).

Fruit non-fleshy (usually), or fleshy (rarely); an aggregate (usually), or not an aggregate. The fruiting carpel dehiscent, or indehiscent; a follicle, or an achene, or baccate (Actaea). Fruit when syncarpous, dehiscent; when syncarpous a capsule (e.g. Nigella). Seeds copiously endospermic. Endosperm oily. Seeds without amyloid. Embryo rudimentary at the time of seed release to weakly differentiated, or well differentiated. Cotyledons 1 (occasionally), or 2 (often connate). Embryo achlorophyllous (14/25); straight.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C₃. C₃ physiology recorded directly in Anemone, Clematis, Delphinium, Ranunculus. Anatomy non-C₄ type (Anemone, Delphinium, Ranunculus). Cyanogenic, or not cyanogenic. Cynogenic constituents tyrosine-derived (including triglochinin). Alkaloids present (mostly), or absent. Berberine present (in the rhizomes of Coptis and Xanthorhiza), or absent. Arbutin absent. Iridoids not detected. Saponins/sapogenins present, or absent. Proanthocyanidins absent (usually), or present (e.g. Clematis); when present, cyanidin. Flavonols present (mostly), or absent; kaempferol, or quercetin, or kaempferol and quercetin (nearly always both). Ellagic acid absent (13 species, 9 genera). Aluminium accumulation not found. Sieve-tube plastids S-type.

Geography, cytology. Frigid zone to tropical. Cosmopolitan, concentrated in the North temperate.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Ranunculiflorae; Ranunculales. Cronquist’s Subclass Magnoliidae; Ranunculales. APG III core angiosperms; peripheral eudicot; Superorder Ranunculanae. APG IV Order Ranunculales.

Species 1500. Genera about 50; Aconitum, Actaea, Adonis, Anemone, Anemonopsis, Aquilegia, Archiclematis, Asteropyrum, Barneoudia, Beesia, Calathodes, Callianthemum, Caltha, Ceratocephala, Cimicifuga, Clematis, Clematopsis, Consolida, Coptis, Delphinium, Dichocarpum, Enemion, Eranthis, Hamadryas, Helleborus, Hepatica, Isopyrum, Knowltonia, Komaroffia, Krapfia, Kumlienia, Laccopetalum, Leptopyrum, Megaleranthis, Metanomone, Miyakea, Myosurus, Naravelia, Nigella, Oreithales, Paraquilegia, Paroxygraphis, Psychrophila, Pulsatilla, Ranunculus, Semiaquilegia, Souliea, Thalictrum, Trautvetteria, Trollius, Urophysa, Xanthorhiza.

Economic uses, etc. Many cultivated ornamentals (Ranunculus, Anemone, Helleborus, Trollius, Delphinium, Aconitum, Aquilegia, some (e.g. Aconitum) supply poisonous narcotic drugs.

Quotations.

When daisies pied, and violets blue,
And cuckoo-buds of yellow hue,
And Lady-smocks all silver-white,
Do paint the meadows with delight
(Love’ Labour’s Lost, v., 2 - ‘cuckoo-buds’ = buttercups)

The buttercups, the little children’s dower
- Far brighter than this gaudy melon-flower!
(Rober Browning, ‘Home Thoughts, from Abroad’)

Both milkmaid’s shouts and herdsman’s call
Have vanish’d with the green
The king kups yellow shades and all
Shall never more be seen
For all the cropping that does grow
Will so efface the scene
(John Clare 1821, ‘Helpston Green’ — a moist part, if this really refers to Caltha palustris)

Whatsoever man fasting eats this wort, leaves his life laughing
(Quoted by Gilmour (‘British Botanists’, 1956), from a medieval manuscript - of Ranunculus sceleratus, with reference to facial strictus induced by its toxin)

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 15th April 2024. delta-intkey.com’.

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