Moving from the top of the leaf (adaxial surface) to the bottom (abaxial surface), you will observe these structures: the epidermis, the mesophyll layer, the vascular bundles.
Outer layer of cells that protects the internal stem tissues
A layer of cuticle coats the epidermis to protect against dessication and UV radiation
Stomata are dotted along the epidermis for gas exchange
In monocots, like grasses, stomata occur on both sides of leaf
In eudicots, like trees, stomata are only on the abaxial side of leaf
The layer of parenchyma cells involved in photosynthesis and gas exchange
In Eudicots, this layer is separated into two layers: palisade layer and spongy layer
A layer of chlorenchyma cells, where light interception for photosynthesis occurs
This layer is toward the adaxial, or upper, side of the leaf
A layer of aerenchyma cells, where gas exchange for photosynthesis occurs
This layer is toward the abaxial, or lower, side of the leaf
The veins of the leaves consists of vascular bundles
The vascular bundles are composed of primary xylem and primary phloem, which formed from the shoot apical meristem and the procambium
Above: Eudicot leaf in cross-section, showing epidermis, vascular bundles, palisade and spongy mesophyll layers
Below: Monocot leaf in cross-section, showing epidermis, mesophyll, and vascular bundles
The flattened, photosynthetic portion of the leaf
The thin, stalk-like portion; sometimes called the stalk
The petiole connects the blade to the stem
Not all leaves possess a petiole (=apetiolate)
The leaf-like outgrowths from petiole near stem
Most leaves do not have stipules (=non-stipulate)
Veins are the visible vascular bundles running through the leaf
How plants survive drought: The unsuspected role of myosin XI in guard cells (Phys.org 14Jul2025)
└Liu et al. (2025) Myosin XI coordinates ABA-induced stomatal closure via microtubule stability and ROS synthesis in drought-stressed Arabidopsis
Making trees in fire-maintained forest less susceptible to drought (Phys.org 13Jun2025)
└Wilson & Hurteau (2025) Trees in Fire-Maintained Forests Have Similar Growth Responses to Drought, but Greater Stomatal Conductance Than Trees in Fire-Excluded Forests
The mystery of the origin of the leaf sheath (SciTechDaily 9Dec2021;
└Richardson et al. (2021) Evolution of the grass leaf by primordium extension and petiole-lamina remodeling