Family: Fabaceae
Medicago
Citation:
L., Sp. Pl. 778 (1753).
Derivation: Name originally formed by Jacques Delachamp, 1513-1588, from the Latin medica, lucerne, so called because lucerne was believed to have been introduced into Europe from Media, a province of the Persian Empire.
Synonymy: Not Applicable Common name: Medics.
Description:
Annual or perennial prostrate decumbent rarely upright herbs or small shrubs; hairs simple, 1-celled or many-celled, frequently tipped by glandular roundish sticky tips; leaves 3-foliolate, denticulate; petiole longer or shorter than the leaflets; upper leaflet distal from lateral ones; stipules adnate to the petiole by their base, usually toothed.
2-several, rarely 1, flowers in axillary pedunculate racemes, the peduncle often ending in a cusp or an awn or bristle as long as the terminal flower, (the flowers occasionally solitary, or the raceme may be so short that it looks like a few-flowered cluster); bracts small, persistent; bracteoles wanting; calyx campanulate, with 5 nearly equal teeth; petals yellow (pinkish or purplish in M. sativa), caducous; standard obovate, longest; wings and keel obtuse; 9 stamens with fused filaments around the ovary; the tenth free, facing the standard; ovary with 1 to many (20 or more) ovules; style with a minutely capitate stigma.
Pod (burr) longer than the calyx, usually spirally coiled, sometimes falcate, reniform or almost straight, straw-yellow to black, nearly always indehiscent, often with a row of spines or tubercles on the dorsal suture which is usually formed of a thickened region of 1 central and 2 lateral veins; spines stocky or slender with their base of 2 prongs usually connected by a membrane; coils loose or tight, formation of spiralling clockwise or anticlockwise starting while the pod is still within the calyx (in S.Aust. species); seed 1 to many, somewhat reniform, yellowish, mostly smooth; cotyledons without articulation.
Distribution:
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1 shrub, 21 herbaceous perennials and 34 annuals. Native to the Old World.
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Biology:
No text
Uses:
Many species are now cultivated or adventive in temperate parts of the world; providing good pasture. (C. C. Heyn (1963) The annual species of Medicago; K. A. & I. Lesins (1979) Genus Medicago (Leguminosae).
Key to Species:
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1. Pod with spines and tubercles on the dorsal suture; annuals |
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2. Pods (including spines) 1-2 cm across, spherical or ovoid, covered with appressed spines, 5-7 mm long |
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3. Pods glabrous, eglandular (except sometimes for the spines); leaves often with a basal reddish-brown spot |
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M. intertexta 3. |
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3. Pods pubescent and glandular; leaves without a dark spot |
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M. ciliaris 2. |
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2. Pods (excluding the spreading spines) less than 8 mm wide |
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4. Spines, if present, slender, their base with 2 prongs (roots) connected by a membrane, I prong inserted in the central vein, the other in the lateral vein or in a veinless zone; pods soft-walled, central part of each coil consisting mainly of veins with thin membranous tissue between them; coils more or less loose and may be pulled apart releasing the seed |
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5. Pods central vein stocky, convex, conspicuously enlarged, not sulcate, completely or almost completely covering the grooves between the central and lateral veins viewed from the edge (coils loose) |
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M. praecox 10. |
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5. Pods edge sulcate, grooves between central and lateral veins observable viewed from the edge |
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6. Leaflets often with a dark spot; pods central vein 1-grooved, lying in grooves of the 2 marginal veins in 1 level, the dorsal suture therefore having 4 ridges with 3 grooves |
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M. arabica 1. |
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6. Leaflets never with a dark spot; pods veins not sulcate, central vein elevated above the lateral veins. |
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7. Wings shorter than the keel; leaflets usually incise-dentate or almost pinnatifid; groove on pod between central and lateral veins narrow, hardly visible when the pod is viewed from the edge |
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M. laciniata 4. |
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7. Wings longer than the keel; leaves regularly dentate; groove between central and lateral veins of pod very wide and visible when the pod is viewed from the edge |
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8. Stipules entire or slightly toothed; pod globular, 3-4 mm wide (excluding spines); pods sparsely villous and often glandular, transverse veins sigmoid, not anastomosing; coils turning clockwise |
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M. minima 7. |
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8. Stipules deeply incised; pod discoid to shortly cylindrical, 7-10 mm wide (excluding spines); pods usually glabrous or nearly so, transverse veins curved but not sigmoid, anastomosing freely; coils turning anti-clockwise |
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M. polymorpha 9. |
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4. Spines, if present, stocky, their base conical, often embedded in spongy tissue; pods hard-walled, coils tight (for release of seed, crushing of pod may be necessary), venation of the face of the coil usually not clearly discernible |
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9. Pods glabrous; transverse veins of the pods nearly straight; spines not sulcate at the base, inserted at 180º to the plane of the coil face |
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M. littoralis 5. |
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9. Pods with sparse hairs; transverse veins of the pods strongly curved; spines sulcate at the base, inserted at 90º to the coil face |
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M. truncatula 14. |
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1. Pods without spines or tubercles; annuals and perennials |
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10. Pod reniform, a small l-seeded nutlet (less than 3.5 mm long), its tip twisted in a small coil (blackish when mature) |
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M. lupulina 6. |
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10. Pods with 2-5 coils (more than 5 mm wide) |
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11. Coils of pod imbricate like a set of bowls, with their convex parts towards the apex and the base, or towards the base only (pods cup-shaped, c. 10 mm wide, maturing brown) |
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M. scutellata 13. |
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11. Coils of pod more or less loose, not markedly imbricate |
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12. Plant glabrous or almost so; pods 10-20 mm wide, papery (light-straw-coloured to black), dorsal suture a slender but distinct vein |
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M. orbicularis 8. |
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12. Plant pubescent; pods 3-9 mm wide |
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13. Flowers yellow, 4-5 mm long; wings shorter than the keel; pod dorsal suture rugose with 20-24 ribs |
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M. rugosa 11. |
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13. Flowers purplish, violet or white, 8-10 mm long; wings longer than the keel; pod dorsal suture smooth |
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M. sativa 12. |
Author:
Not yet available
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