Stomata in the context of "Axil"

A leaf (pl.: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf, but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral. The leaf is an integral part of the stem system, and most leaves are flattened and have distinct upper (adaxial) and lower (abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax, and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll which is essential for photosynthesis as it absorbs light energy from the Sun. A leaf with lighter-colored or white patches or edges is called a variegated leaf.

Leaves vary in shape, size, texture and color, depending on the species The broad, flat leaves with complex venation of flowering plants are known as megaphylls and the species that bear them (the majority) as broad-leaved or megaphyllous plants, which also include acrogymnosperms and ferns. In the lycopods, with different evolutionary origins, the leaves are simple (with only a single vein) and are known as microphylls. Some leaves, such as bulb scales, are not above ground. In many aquatic species, the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls and spines. Furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from leaves both in their structure and origin. Some structures of non-vascular plants look and function much like leaves. Examples include the phyllids of mosses and liverworts.

Evapotranspiration (ET) refers to the combined processes which move water from the Earth's surface (open water and ice surfaces, bare soil and vegetation) into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpiration (evaporation that occurs through the stomata, or openings, in plant leaves). Evapotranspiration is an important part of the local water cycle and climate, and measurement of it plays a key role in water resource management and agricultural irrigation.

Abies × borisii-regis (Bulgarian fir) is a hybrid species of fir native to the mountains of the Balkan Peninsula in Bulgaria, northern Greece, Kosovo, North Macedonia, Albania and Serbia. It occurs at altitudes of 800–1,800 m (2,600–5,900 ft), on mountains with an annual rainfall of over 1,000 mm (39 in).

It is a large evergreen coniferous tree growing to 40–50 m (130–160 ft) (exceptionally 60 m (200 ft)) tall and with a trunk diameter of up to 1.5 m (4 ft 11 in). The leaves are needle-like, flattened, 1.8–3.5 cm (0.71–1.38 in) long and 2 mm (0.079 in) wide by 0.5 mm (0.020 in) thick, glossy dark green above, and with two blue-white bands of stomata below. The tip of the leaf is variable, usually pointed, but sometimes slightly notched at the tip, particularly on slow-growing shoots on older trees. The cones are 10–21 cm (3.9–8.3 in) long and 4 cm (1.6 in) broad, with about 150–200 scales, each scale with an exserted bract and two winged seeds; they disintegrate when mature to release the seeds.

A leaf (pl.: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf, but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral. The leaf is an integral part of the stem system, and most leaves are flattened and have distinct upper (adaxial) and lower (abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax, and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll which is essential for photosynthesis as it absorbs light energy from the Sun. A leaf with lighter-colored or white patches or edges is called a variegated leaf.

Leaves vary in shape, size, texture and color, depending on the species. The broad, flat leaves with complex venation of flowering plants are known as megaphylls and the species that bear them (the majority) as broad-leaved or megaphyllous plants, which also include acrogymnosperms and ferns. In the lycopods, with different evolutionary origins, the leaves are simple (with only a single vein) and are known as microphylls. Some leaves, such as bulb scales, are not above ground. In many aquatic species, the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls and spines. Furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from leaves both in their structure and origin. Some structures of non-vascular plants look and function much like leaves. Examples include the phyllids of mosses and liverworts.

Zosteraceae (one of the four seagrasses families, Kubitzki ed. 1998) is a family of marine perennial flowering plants found in temperate and subtropical coastal waters, with the highest diversity located around Korea and Japan. Most seagrasses complete their entire life cycle under water, having filamentous pollen especially adapted to dispersion in an aquatic environment and ribbon-like leaves that lack stomata. Seagrasses are herbaceous and have prominent creeping rhizomes. A distinctive characteristic of the family is the presence of characteristic retinacules, which are present in all species except members of Zostera subgenus Zostera.

Zosteraceae has long been accepted by taxonomists as monophyletic. The APG II system of 2003 recognizes this family and places it in the monocot order Alismatales. The family contains approximately twenty-two species divided between two genera, Phyllospadix and Zostera totalling 22 known species (Christenhusz & Byng 2016 ). Zostera contains three subgenera: Heterozostera (formerly considered a separate genus ), Zostera and Zosterella. Zosteraceae is closely related to Potamogetonaceae, a family of freshwater aquatics.

Abies cephalonica, commonly known as Greek fir or Cephalonian fir, is a fir native to the mountains of Greece, primarily in the Peloponnesos and the island of Kefallonia, intergrading with the closely related Bulgarian fir further north in the Pindus mountains of northern Greece. It is a medium-size evergreen coniferous tree growing to 25–35 metres (82–115 ft) – rarely 40 m (130 ft) – tall and with a trunk diameter of up to 1 m (3 ft 3 in). It occurs at altitudes of 900–1,700 m (3,000–5,600 ft), on mountains with a rainfall of over 1,000 millimetres (39 in).

The leaves are needle-like, flattened, 1.5–3.0 cm (0.6–1.2 in) long and 2 mm (0.08 in) wide by 0.5 mm (0.02 in) thick, glossy dark green above, and with two blue-white bands of stomata below. The tip of the leaf is pointed, usually fairly sharply but sometimes with a blunt tip, particularly on slow-growing shoots on older trees. The cones are 10–20 cm (4–8 in) long and 4 cm (1.6 in) broad, with about 150–200 scales, each scale with an exserted bract and two winged seeds; they disintegrate when mature to release the seeds.