Plant Classification & Parts of Tree

The Classification Of Plants is mainly based on the plant Taxonomy, life cycle, flowering, non-flowering, and the number of seeds.

Herb

• A plant whose stem is always green & tender
• Height not more than 1 meter
• Banana plant is the world’s largest herb

Shrub

• A woody plant, smaller than a tree, & of max height 6 meters
• Has several main stems arising at or near the ground

Tree

• A woody perennial plant, typically having a single stem or trunk growing to a considerable height
• Bearing lateral branches at some distance from the ground

Parasite

• An organism which lives in or on another organism (its host) and benefits by deriving nutrients at the other’s expense.
• They penetrate their roots (Haustoria) into the host plant to derive minerals, moisture & nourishment.

Epiphyte

A plant that grows non-parasitically upon another plant (such as a tree), and derives its moisture and nutrients from the air, rain, and sometimes from debris accumulating around it instead of the structure it is fastened to.

• Normally grows on another plant for support.
• It is not parasitic in nature & uses the host plant for support only
• Found commonly in tropical rain forests

Climbers

• Plants which grow upright, relying on other plants, rocks and manmade structures, and anything else they can find for support
• Example → Vine plant

Parts of a tree

Roots

• Convey water and nutrients from the soil to the rest of the plant via numerous branches and fibers.

Crown

• Made up of the leaves & branches at the top of the tree.
• The crown shades the roots, collects energy from the sun (Photosynthesis) & allows the tree to remove excess of water to keep it cool via transpiration

Leaves

• A usually green, flattened, lateral structure attached to a stem and functioning as a principal organ of photosynthesis and transpiration in most plants, also known as food factory of the plant
• converts energy into food (sugar) as they contain chlorophyll, which gives green color to the leaves & allows plants to absorb energy from light i.e. convert carbon dioxide & water into carbohydrates
• Light energy is absorbed by chlorophyll, while air containing carbon dioxide and oxygen enters the plant through the leaf stomata.

Photosynthesis Reaction > CO2 + H2O + Sunlight >>>> Glucose (Sugar) + Oxygen

Branches

• Arms of the tree, a woody structural member connected to but not part of the central trunk of a tree
• Provide the support to distribute the leaves efficiently & serves as a conduit for water & nutrient and as storage for extra sugar

Trunk

• Provides shape & support to the tree & holds up the crown
• Supplies water & nutrients from the soil & sugars from the leaves via its branches.

Parts of the Trunk of a Tree

Annual Rings

• A concentric layer of ring is developed annually inside trunk of a tree
• Used to determine the age of the tree (Dentro-Chronology)
• Also known as growth rings

Bark

Defined as the outside layer of trunk, branches & twigs (small offshoot branches generally leafless), & are of two types, namely, inner bark & outer bark.

• The inner layer of bark is made up of living cells known as Phloem, which carry sap full of sugar from the leaves to the rest of the tree.
• The outer bark is made up of dead cells, like our nails, which serves as a protective layer of the tree
• A number of products are made from the bark of a tree namely Latex, Cinnamon, Perfumes, Poison etc. 

Cambium

• Thin layer of living cells just inside the bark
• It is the part of the tree that makes new cells allowing the tree to grow wider each year.

Sapwood (Xylem)

• Made up of a network of living cells that bring water & nutrients up from the roots to the branches, twigs & leaves.
• It is the youngest wood of the tree, over the years, inner layers of sapwood die & become heartwood.

Heartwood

• Dead sapwood in center of the trunk, usually darker than sapwood.
• It is the hardest wood of the tree giving it support & strength.

Pith

• Tiny dark spot of spongy living cells right in the center of the tree trunk
• Transports the essential nutrients throughout the tree