Compare monocotyledons with dicotyledons?

Monocotos: # Seed Leaves, Leaf Vascular Bundles, Steam vascular Bundles, # Flower %26amp; Seed Parts





Dictos: # Seed Leaves, Leaf Vascular Bundles, Steam vascular Bundles, # Flower %26amp; Seed Parts

Compare monocotyledons with dicotyledons?
Dicot

Seed: two cotyledon, epigeal development

Leaves: Reticulate, no leaf sheath

Stem Vascular Bundle: Eustelic

Flower: Actinomorphic, Regular

Root Vascular Bundle: Protostelic



Monocot

Seed: 1 cotyledon, hypogeal development

Leaves: Parallel veined, with leaf sheath

Stem Vascular Bundle: Atactostelic

Flower: Zygomorphic, Irregular

Root Vascular Bundle: Siphonostelic
Reply:The major difference between these two kinds of plants lies in their "seed leaves", or cotyledons. This material provides baby plants with nourishment until they develop actual leaves. "Mono" means "one" in latin, and monocots have a single seed leaf which usually remains buried and acts as an undergound food reserve. "Di" is latin for "two" and as the name suggests, dicotyledons have a pair of seed leaves. These function like true leaves because they are above ground and help the young plant make food. However there are exceptions to this rule. The acorn is a dicot plant, but the nut remains buried as the young tree sprouts. If examined however, the acorn reveals a pair of tightly compressed cotyledons inside the nut. Burying seed leaves underground might be a survival stragety. If the shoot is grazed, the plant retains a store of underground food to grow another shoot. In the forest, deer are the main preditors of young oak trees.



The second major distinction between monocots and dicots is the nature of their vascular tissue. The vessel walls are much thicker in dicots. This allows the formation of woody tissue. Most branching trees are dicots, and wood is necessary to support the weight of the heavy, horizontal branches. Wood develops from a special layer of cells just under the bark of dicots. This layer is called the cambrium and forms wood in layers. Initially it forms vascular bundles known as phloem. the phloem conducts sugars manufactured in the dicot's leaves to the roots, where it is stored as starch. As the cambrium continues to lay down successive layers of cells, the phloem thickens and eventually dies, leaving a cellulose skeleton known as xylem. The xylem is used to transport water up from the roots to the leaves. The woody fibers in dicot plants is xylem tissue.



The growth of the cambrium means the trunk of a dicot can continue to increase in diameter indefinetly. Again, this helps support the weight of limbs and branches. Monocots do not have woody tissue in their stems. There are tree-like species such as palms, but the crown of leaves grows unbranched from a single trunk. As a whole, monocots are far less massive than dicots because the monocots lack wood fibers. Monocot stems contain a thick epidermis with vascular bundles inside, supported by spongy tissue. Some monocots have stems which are actually hollow. Grasses are a good example, and giant species like bamboo illustrate this design very well.



Both monocots and dicots have hermaphrodite flowers, containing both sperm and egg producing tissue. However, there are examples of unisexual plants in each group. Marajuana is a good example of a dicot which has male and female plants. Certain monocot orchids can also produce either all male or all female flowers.



Monocots all tend to have flowers with six petals arranged in a circular pattern. This is an example of radial symmetry and is used by both monocots and dicots. However, monocot orchids have developed a bilateral symmetry. One petal has become curled around the reproductive structure of the flower. Known as the "lip" this special petal is designed to guide pollinators into the flower and align them precisely to recieve pollen. Most Orchids have a single species of insect which pollinates it, and the flower has evolved to accomidate the anatomy of the plant's pollinator. The other extreme amoungst monocots are the grasses, which are pollinated by the wind. This is also the way cone bearing plants such as conifers reproduce. Grass flowers are tiny and the petals are reduced to tiny scales.



Dicot flowers can have many petals, or even none at all. The aster family has what appears to be a single flower, but it is actually a flower "colony" with a dense bunch of tiny flowers in the center and special "ray" flowers which have one petal enlarged enormously. The ray flowers surround the flower, and gives the daisy its particular appearance. Some dicots have fused their petals into a tube like structure. Many gesneriads like streptocarpus and sinningias have tube flowers. The african "violet" is a gesneriad with a tube flower, but the tube is short and the petals separate at the end.