Rosaceae
Alternative names: Not Applicable
Description:
Annual herbs to woody shrubs or trees with alternate simple or compound stipulate leaves; the stipules sometimes adnate to the petiole.
Flowers axillary or in racemes or cymes, usually bisexual and regular; calyx single (with 4 or 5 sepals) or double (with a similar number of alternate outer sepals); petals 4 or 5, caducous, sometimes 0; sepals and petals inserted at the summit of the torus; stamens 2-numerous; perigynous or epigynous; gynoecium of 1 or more 1-celled carpels, superior or sometimes becoming inferior through union with the hollow receptacle, each carpel usually with 1 style and 1 or 2 anatropous ovules.
The fruits or fruitlets consisting of the ripe indehiscent carpels, which may be dry or succulent, either raised on the extended and convex receptacle (gynophore) or sunk in the hollow receptacle, which may be succulent and form a false berry (Rosa), or fleshy and united to the carpels, forming a sort of false drupe sometimes called a pome (Crataegus), or may be hard and dry, forming a false nut (Aphanes and Acaena); seeds with a straight embryo, broad fleshy cotyledons and little or no albumen. The hollow receptacle of many genera with superior carpels so encloses the fruiting carpels that it may easily be mistaken for an inferior ovary.
Distribution:
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About 2,000 species in 100 genera, cosmopolitan.
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Biology:
No text
Uses:
An important family with few native Australian genera. It includes many important horticultural crops such as apricot (Prunus armeniaca), apple (Malus sylvestris), loquat (Eriobotrya japonica), peach (Prunus persica), pear (Pyrus communis), plum (Prunus domestica), quince ( Cydonia oblonga), raspberry (Rubus idaeus) and strawberry (Fragaria yesca). Ornamentals include roses (Rosa), hawthorns (Crataegus) and spiraea (Spiraea); blackberries (Rubus spp.) are notorious weeds.
Key to Genera:
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2. Petals and outer calyx present; carpels numerous on a dry convex torus |
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POTENTILLA 8. |
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2. Petals absent; carpels 1 or 2, enclosed in dry hollow receptacular tube, but not united with it |
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3. Outer calyx present; receptacle smooth; leaves palmatifid |
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APHANES 7. |
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3. Outer calyx absent; leaves pinnate |
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ACAENA 6. |
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SANGUISORBA 11. |
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5. Shrubs or sprawlers with hooked prickles |
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6. Carpels becoming little drupes united in a juicy head on a convex receptacle |
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RUBUS 10. |
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6. Carpels becoming achenes free within the hollow more or less succulent receptacle |
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ROSA 9. |
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5. Shrubs or trees; unarmed or juvenile phases with straight pungent spines |
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8. Leaves more than 8 cm long, glossy |
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PRUNUS 12. |
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8. Leaves less than 3 cm long, sparsely pubescent |
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COTONEASTER 1. |
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7. Deciduous shrubs or trees |
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9. Ovary more or less superior; flowers solitary or in small clusters; fruit a drupe; endocarp bony |
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PRUNUS 12. |
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9. Ovary more or less inferior; flowers in corymbs (Cydonia solitary); fruit a pome |
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10. Flowers solitary; leaves entire |
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CYDONIA 3. |
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10. Flowers in corymbs; leaves lobed or serrate |
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11. Leaves with 3-5 lobes; fruits in a small cluster, red; mostly less than 2 cm diam |
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CRATAEGUS 2. |
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11. Leaves serrate, not lobed; fruit mostly solitary, more than 2 cm diam |
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12. Leaves more or less glossy, glabrous; fruit with abundant stone cells |
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PYRUS 5. |
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12. Leaves more or less dull, more or less pubescent below, fruit without stone cells |
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MALUS 4. |
Author:
Woody genera prepared by D. E. Symon, others by J.P. Jessop
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