Family: Ranunculaceae
Ranunculus
Citation:
L., Sp. Pl. 548 (1753).
Derivation: Diminutive of Latin rana, a frog; name of a plant in the writings of Pliny.
Synonymy: Not Applicable Common name: Buttercups, ranunculus.
Description:
Annual or perennial herbs, sometimes aquatics; stems erect, creeping or stoloniferous; leaves spirally arranged, often with a basal rosette, exstipulate but petioles, with a gradually tapering leaf sheath; blades often palmately lobed or divided, ternate or pinnately dissected, sometimes simple and entire.
Flowers solitary and terminal, sometimes in cymose panicles, bisexual, regular, all parts arranged spirally; sepals 3-5; petals 5-15, rarely fewer, yellow or white, often glossy, each with a nectar-secreting pit on the upper surface usually in the lower half, often near the base, sometimes covered by a lobe which may be adnate at its lateral margins forming a pocket; stamens numerous, rarely only 5 or fewer; carpels free, usually numerous, with 1 basal ovule.
Fruit a globular or elongated head of achenes; style usually persistent and forming a glabrous beak.
Distribution:
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More than 500 species, cosmopolitan but chiefly in the extratropical Northern Hemisphere. In Australia about 47 species of which 10 are introduced.
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Biology:
Poisonous to cattle when fresh.
Key to Species:
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1. Plants perennial; achenes glabrous, smooth or obscurely and irregularly rugose |
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2. Plants with stolons; basal leaves ternate or palmately lobed or dissected |
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3. Stolons above ground, thick; petals 5-10 mm wide; basal leaves ternate; leaflets broad, ovate to more or less rhombic; ripe achenes smooth, finely punctulate; beak less than half achene length |
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R. repens 10. |
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3. Stolons underground, thin; petals less than 5 mm wide; basal leaves palmatisect or palmatifid, if ternate, then leaflets narrow-elliptic to obovate-cuneate; ripe achenes obscurely rugose; beak half to two thirds achene length |
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4. Petals more or less linear, 3-nerved, the central nerve sometimes forked above the middle; nectary about one-third the petal length above base, forming a swollen semilunar bracket or pocket; leaves variable; segments from linear (when sub-merged) to obovate-cuneate (when aerial); sepals glabrous . R. rivularis 11 |
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4. Petals oblanceolate to elliptic, 3-nerved at base, lateral nerves forked below the middle; nectary near the petal base, covered by a lobe, its sides often attached in part to the petal and forming a pocket |
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5. Ultimate leaf-segments narrow-linear, c. 1 mm wide; sepals glabrous; flowers 1-1.5 cm diam.; torus glabrous between the achenes, more or less densely short-hispid in the staminal zone |
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R. inundatus 2. |
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5. Ultimate leaf-segments narrow-elliptic-cuneate to oblanceolate, 2-6 mm wide; sepals usually hispid outside; flowers 1.5-2 cm diam., torus hispid between the achenes, glabrous in the staminal zone |
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R. papulentus 6. |
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2. Plants without stolons; basal leaves 3-lobed, 3-partire to more or less biternately cut or lobed |
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6. Stem and petioles with short appressed hairs throughout; basal leaves few, dissected into narrow almost linear segments; roots fleshy, more or less tuberous |
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R. robertsonii 12. |
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6. Stem and petioles with long spreading hairs at least in their lower part; basal leaves several to many, with broad lanceolate to obovate segments |
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7. Achenes more or less globular, with very thick pericarp; roots fleshy, more or less tuberous; basal leaves usually simple, 3- lobed to 3-partire, broad-ovate or as wide as long |
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R. pachycarpus 5. |
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7. Achenes lenticular, with thin pericarp; roots fibrous (sometimes thick); basal leaves usually ternate (at least the later ones), to biternately lobed, ovate in outline, longer than wide, the central leaflet distinctly longer stalked than the lateral leaflets |
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R. lappaceus 3. |
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8. Achenes smooth and glabrous on lateral faces; torus glabrous; sepals spreading; petals 1-4; flowers inconspicuous, 2-4 mm diam |
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9. Achenes more or less lenticular, thicker in the centre than at the margin, not twisted, 1.5-2 mm long; sepals 3 or 4; plants hairy |
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R. pumilio var. politus 9b. |
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9. Achenes strongly flattened, very thin, papery, with a thickened margin, often somewhat twisted when ripe, 2.5-4 mm long; sepals 3-5; plants almost glabrous |
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R. pentandrus var. pentandrus 8a. |
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8. Achenes with spines, tubercles and/or hairs on lateral faces |
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10. Plants slender; flowers inconspicuous, 2-6 mm diam.; torus glabrous; petals usually fewer than 5 |
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11. Plants almost glabrous; achenes strongly flattened, very thin, papery, with a thickened margin, often somewhat twisted when ripe, 2.5-4 mm long, with small conical tubercles scattered over the central part of the faces, each terminated by a short recurred hair |
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R. pentandrus var. platycarpus 8b. |
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11. Plants hairy; achenes flattened but neither papery-thin nor twisted |
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12. Achenes 1.5-2 mm long; fruits often almost sessile |
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13. Basal leaves ternate, with linear to narrow-lanceolate leaflet-segments |
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14. Achenes more or less lenticular, their faces covered by hairs which sit on very short tubercles; sepals 5 R. pumilio var. purnilio 9a. |
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14. Achenes flat, with prominent conical tubercles scattered over the faces; sepals 3 or 4 |
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R. sessiliflorus var. pilulifer 13b. |
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13. Basal leaves palmate to palmatifid, coarsely toothed or lobed |
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R. sessiliflorus var. sessiliflorus 13a. |
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12. Achenes 3-4 mm long; fruits mostly pedicellate |
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15. Achenes on lateral faces with long thin subulate tubercles (bristles), each terminated by a short recurved hair, stipitate at the base; sepals 3, spreading; petals 1-nerved, nerve sometimes forked towards the apex |
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R. hamatosetosus 1. |
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15. Achenes on lateral faces with short conical tubercles, each terminated by a recurved bristle, not or only shortly stipitate; sepals 4 or 5, reflexed; petals with 3 principal nerves, all once or twice forked in the lower half |
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R. parviflorus 7. |
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10. Plants robust, nearly glabrous; flowers conspicuous, 8-15 mm diam.; torus hairy; sepals reflexed; petals usually 5 |
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16. Achenes 2-3 mm long, with short conical tubercles; basal leaves ternate, the middle leaflet longer stalked than the lateral leaflets |
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R. trilobus 14. |
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16. Achenes c. 7 mm long, with slender almost spiny tubercles; basal leaves roundish-cordate, 3-5-lobed |
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R. muricatus 4. |
Author:
Not yet available
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