When speaking about roses it makes it much easier if all of us use the same terminology. The following is a list of basic terms used to describe rose plant parts. It is a lot easier to understand what someone is talking about when they say “sepals” rather than “… you know, those little green things just under the flower …”
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Anther – The upper portion of a stamen which contains the pollen sacs.
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Apical Meristem – Non-maturing cells located at the tips of shoots and roots which produce the plant hormone auxin.
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Auricle – The ‘ear-like’ projection found on the tip of the stipule.
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Auxin – a plant hormone that regulates the bloom cycle for rose buds.
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Axil – the angle on the upper side where the leaf and stem join.
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Axillary – A term applied to buds or branches occurring in the axil of a leaf. These buds begin to grow after pruning or deadheading.
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Bark – The outer layer of the stem of a rose.
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Bud – An embryonic shoot that may eventually produce either flowers of foliage.
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Bud Union – That area between the roots and the stems where the bud of the desired variety was grafted onto the rootstock.
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Bract – A leaf unlike the ordinary leaves which is usually smaller or of a different shape, growing from the peduncle just below the flower.
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Calyx – The first of a series of flower parts growing from the peduncle, composed of sepals, usually green and leaf-like.
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Cane – The stem of a rose, either the main stem (which then becomes the trunk) or lateral stems or branches.
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Carpel – An organ bearing ovules along its margins; part of a compound pistil.
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Compound Leaf – A leaf composed of two or more parts or leaflets. Rose leaves are pinnately compound.
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Corolla – The second of a series of flower parts growing from the peduncle, composed of petals.
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Double – Referring to how many petals the rose has – usually between 25 and 45.
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Filament – The stalk of the stamen which supports the anther.
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Floral Tube – A cup-like structure formed by the fusion of the basal parts of the sepals, petals and stamens. Don’t call it a ‘calyx tube.’
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Fruit – A ripe ovary containing seeds and any adjacent parts.
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Hip – The fruit of the rose which contains the seeds.
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Leaf – An organ arising laterally from superficial tissues of a shoot apex. It is usually flat and may be simple or compound.
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Leaf Scar – A mark left on the stem where the leaf detaches. There is a bud just above each leaf scar.
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Meristem – Tissue composed of cells that do not mature, but remain capable of further growth and division. Present in growing tips.
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Mixed Buds – Buds that produce both leaves and flowers; usual type of bud on roses; present in leaf axils.
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Ovary – The swollen basal portion of the pistil containing the ovules or seeds.
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Ovule – A structure containing the embryo sac, nucellus, integuments and stalk. After fertilization this develops into seeds.
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Peduncle – The main stem of a an individual flower or of a spray.
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Pedicel – The stem of an individual flower in a spray.
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Perianth – The collective term for the calyx and corolla (sepals and petals) combined.
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Petal – One of the units of the corolla of the flower. Roses have from four to over 100 petals, depending on the variety.
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Petaloid – A transitional phase between petals and stamens. Petalloids are visible in single and semi-double roses as deformed-looking petals in the center of the rose.
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Petiole – The stalk of the leaf.
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Petiolul – A subdivision of the petiole which connects the lateral leaflets to the petiole.
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Pistil – The central organ of the flower composed of one or more carpels and enclosing the ovules.
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Pith – The soft inner portion of a rose stem.
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Pollen – The granules within the pollen sacs containing genetic information used for sexual reproduction.
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Prickle – A spine-like superficial outgrowth of the stem. Roses have prickles, not ‘thorns.’
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Roots – The underground parts of the rose used for support and to absorb water and nutrients.
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Rootstock – The cultivated roots of a rose which will be implanted with a bud from another variety (grafting).
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Semi-double – Referring to how many petals the rose has – usually 12 to 25.
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Sepal – One of the units of the calyx. These are the green coverings of a flower bud that open to reveal the petals of the rose. Roses usually have 5 sepals.
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Single – Referring to how many petals the rose has – usually four to eight.
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Spray – Several flowers buds which arise from one peduncle and develop into many flowers on short pedicels.
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Stamen – The organ of the flower producing pollen, composed of an anther and a filament.
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Stigma – The top of the pistil, the part that receives the pollen grains.
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Stipule – A leaf appendage that is usually present in roses on the petiole where it meets the stem.
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Style – The part of the pistil that connects the ovary and the stigma.
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Terminal – A term applied to buds occurring at the end of branches. The end or tip.
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Thorn – A branch of a plant that becomes woody, hard and pointed. Cactus plants have thorns, locust trees have thorns. Rose do NOT have thorns as the ‘prickles’ on a rose do not develop from ‘branch’ tissue.
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Trunk – The main stem of a rose, the cane that later produces all the side branches or lateral canes.
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Vegetative Bud – A bud that produces only leaves and never flowers. Roses do NOT have vegetative buds.