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Phyllode
Phyllodes are modified petioles or leaf stems, which are leaf-like in appearance and function. In some plants, these become flattened and widened, while the leaf itself becomes reduced or vanishes altogether. Thus the phyllode comes to serve the purpose of the leaf. Some important examples are '' Euphorbia royleana'' which are cylindrical and '' Opuntia'' which are flattened. They are common in the genus ''Acacia'', especially the Australian species, at one time put in ''Acacia'' subg. ''Phyllodineae''. Sometimes, especially on younger plants, partially formed phyllodes bearing reduced leaves can be seen. The illustration (to the right) of '' Acacia suaveolens'' from '' Novae Hollandiae plantarum specimen'' shows the juvenile true leaves, together with the developing phyllodes, and the phyllodes of the mature plant. The genus, '' Daviesia'', in the family Fabaceae, is characterised in part by the plants having phyllodes. File:Acacia suaveolens 9064505997 9f14f5f117 o.jpg, '' A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petiole (botany)
In botany, the petiole () is the stalk that attaches the leaf blade to the stem, and is able to twist the leaf to face the sun. This gives a characteristic foliage arrangement to the plant. Outgrowths appearing on each side of the petiole in some species are called stipules. Leaves with a petiole are said to be petiolate, while leaves lacking a petiole are called sessile or apetiolate. Description The petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves, the leaf stalk may be long, as in the leaves of celery and rhubarb, or short. When completely absent, the blade attaches directly to the stem and is said to be sessile. Subpetiolate leaves have an extremely short petiole, and may appear sessile. The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile. In some other plant groups, such as the speedwell genus '' Veronica'', petiolate and sessile leaves may occur in different species. In the grasses ( Poaceae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
