Study the labels in Figure 6.2. and compare the illustration with the actual leaf structure of grasses on display in the lab. **Figure 6.2: Grass Leaves**- **a. General**: This illustration shows the overall structure of grass leaves, highlighting their elongated and narrow shape.- **b. Detail of Intersection with Stem**: This diagram provides a closer look at the components where the grass leaf intersects with the stem. Key parts include: - **Blade**: The flat, broad part of the leaf. - **Ligule**: A membrane or hairy structure at the junction of the blade and sheath. - **Auricle**: Ear-like lobes at the base of the leaf blade. - **Sheath**: The lower part of the leaf that encircles the stem.**Figure 6.3: Lilac (Syringa) Leaf Cross-Section**This cross-section diagram of a lilac leaf shows the internal structure and arrangement of cells. Features include:- **Epidermis**: The outermost layer of cells on the upper and lower surfaces.- **Palisade Mesophyll**: Columnar cells arranged closely under the upper epidermis, responsible for photosynthesis.- **Spongy Mesophyll**: Loosely arranged cells with air spaces, facilitating gas exchange.- **Vascular Bundles**: Circular or oval structures representing veins within the leaf, responsible for transporting water, nutrients, and sugars.

Grass Structure -- The grasses may be annual living for one year or biennials grow vegetatively for first year and produce a flowers during second year . The grasses have four main parts - 1 - Roots 2 - Stem 3 - Leaves 4 - Inflorescence Roots - Roots grow from fibrous root masses but sometime a below ground root - stem called as rhizome. Stem -- Stem in grasses are called as culms . The stem in grasses are very important for identification of grasses . Single up right stem with a few leaves at the base , but stems can also originate from clusters or tuft of leaves at the base . Stem can be underground rhizomes or above ground called as stolons , which run on the ground . Leaves -- Leaves arise from base of stem or from swelling along the stem called as nodes . The space between nodes are called as internodes .Difference between true leaf and leaf of grass -- Leaves are the structures where the photosynthesis occur ,function as storage of food . Most plants are green due to presence of green pigment called as chlorophyll . Structure of true leaf -- Size , shape and size of the leaves are usually adapted to the conditions of the environment which support the plant to survive in that particular conditions . Each leaf typically have a leaf blade called as lamina , widest portion of leaf . Leaf attached with a stalk is called as petiolate and without stalk sessile . Small green appendages at the base of leaves are stipules . Most leaves have a mid rib which travel the length of leaf with branches to each side of the mid rib to produce vascular tissue . External structure of dicot leaf -- Dicot leaves are broad relatively smaller than monocots .Dicot leaves are dorsoventral as upper and lower surface of the leaves are distinguished . Dicot leaf internal structure -- Dicot leaf is characterized by presence of upper and lower cuticle and epidermis , larger intercellular spaces due to loosely packed cells . Stomata are present more in lower epidermis as in upper epidermis . Dicot leaves contain larger vascular bundles . External structure of monocot leaf or grasses -- Monocot leaves are narrow , slender and longer , basic structural characteristics are typical of majority of monocot plants . Arrowhead structure are monocot leaf . Leaves have lobes which hang downwards . Monocot leaves are isobilateral in symmetry . Leaves with parallel veins . Internal structures of monocot leaf or grass -- The internal structure of monocot leaf has only one kind of cells which are small oval or spherical or irregular shaped spongy parenchyma with chloroplast and chlorophyll . Important structure of grasses --Outer thick cuticle on upper and lower surface . Epidermis - Upper and lower , stomata are more or less equal . Mesophyll is differentiated in to spongy parenchyma and palisade parenchyma . Two larger vascular bundles are separated by sclerenchyma tissue .