|
| on falling or otherwise not obvious as in Moraceae or absent altogether as in the Magnoliaceae. A petiole may be absent (apetiolate), or the blade may not be laminar (flattened). The petiole mechanically links the leaf to the plant and provides the route for transfer of water and sugars to and from the leaf. The lamina is typically the location of the majority of photosynthesis. The upper (adaxial) angle between a leaf and a stem is known as the axil of the leaf. It is often the location of a bud. Structures located there are called "axillary". New pomegranate leaves External leaf characteristics, such as shape, margin, hairs, the petiole, and the presence of stipules and glands, are frequently important for identifying plants to family, genus or species levels, and botanists have developed a rich terminology for describing leaf characteristics. Leaves almost always have determinate growth. They grow to a specific pattern and shape and then stop. Other plant parts like stems or roots have non-determinate growth, and will usually continue to grow as long as they have the resources to do so. A leaf shed in autumn The type of leaf is usually characteristic of a species (monomorphic), although some species produce more than one type of leaf (dimorphic or polymorphic). The longest leaves are those of the Raffia palm (Raphia regalis) which may be up to 25 m (82 ft) long and 3 m (9.8 ft) wide. The terminology associated with the description of leaf morphology is presented, in illustrated form, at Wikibooks. Prostrate leaves in Crossyne guttata Where leaves are basal, and lie on the ground, they are referred to as prostrate. Basic leaf types Whorled leaf pattern of the American tiger lily Perennial plants whose leaves are shed annually are said to have deciduous leaves, while leaves that remain through winter are evergreens. Leaves attached to stems by stalks (known as petioles) are called petiolate, and if attached directly to the stem with no petiole they are called sessile. Ferns have fronds. Conifer leaves are typically needle- or awl-shaped or scale-like; they are usually evergreen but can sometimes be deciduous. Usually, they hav |