Parallel Venation Plants
Parallel venation is found in plants with leaves divided into a network of veins that are parallel on both surfaces. This structure is thought to increase the surface area of the leaf which in turn assists in gas exchange.
Venation is the branching pattern of the veins of leaves. All plants have a circulatory system with a network of veins that transport water or other substances throughout the plant. This is for the plants to survive and have life. There are many different venation patterns on the leaves that show their age, climate, and average water availability.
Parallel venation is when the veins that branch out from the mid-rib are evenly spaced from each other and run parallel to one another.
Parallel venation is a term used in botany to describe the presence of parallel veins. All plants have a vascular, or xylem, system that transports substances up to the leaves. The diagram below shows the xylem elements in a tree-like plant.
The key to understanding parallel venation is examining how water is moved through these vessels. Each vessel is like a pipe with smaller cross-sections. From one end of the pipe to the other, pressure builds as more water blocks are added.
If a vena occurs between two vessels, the pressure builds in both vessels at the same rate and is distributed to each vessel as evenly as possible. This ensures that each is supplied equally and with the same amount of water.
One of the characteristics of a vascular system is that it moves water up through the xylem toward the top of the plant. In many plants, this upward movement stops at some point before reaching leaves or other structures on the surface of the plant. In these plants, the xylem is often described as being “parallel” to the surface of the plant.
In plants, water moves up through a column-like structure known as a xylem. The pressure in this column pushes water upward until it reaches a layer at which point it cannot go any further. This is known as the “ligne limitee” or “limiting layer”. In most plants, this point occurs just beneath the center of leaves and other plant parts like tendrils or flowers.
In plants with parallel venation, the xylem develops a variation of pressure. This pressure is distributed to each vessel at the same rate but is greatest in the parallel veins. This provides an advantage for plants in that it allows water to be transported more efficiently which in turn provides a larger living area for the plant.
Parallel venation occurs in many different plant structures like leaves and roots.
In leaves, parallel venation occurs in some species of “Calathea”. When a large leaf needs to be transported or supported, many smaller veins branch out from the main vein. This provides an advantage because as the leaf grows larger, like when it catches rainwater, it can still be supported by the main vein. Without this pattern of veins, the leaf would not be able to support its own weight.
Parallel venation may also occur in roots. This is seen in the “Meyrania” orchid when the roots grow out of a circle, creating a round shape.
Parallel venation occurs in many other plant structures as well including tendrils, trunks, and flowers. Many primitive groups of plants have parallel venation like conifers and Ginkgos.
Parallel veins occur because it allows for an increase in a surface area without increasing the overall size of the plant. In addition, the pressure in the xylem is more evenly distributed throughout the plant and this allows for better water transportation.
Parallel Venation Leaves
Parallel venation, also called “latitudinal venation,” is one of the most common types of venation in plants, and is notable because it is found in the leaves of many plant families, such as Asteraceae, Fabaceae, and Rosaceae.
Parallel venation leaves are a plant’s leaf structure, that is, its veins. The number of these veins is what determines how parallel the venation is. Parallel venation leaves are a very common type found in leaves, and they are also among the easiest to make out.
Parallel venation is generally characterized by straight, parallel veins running more-or-less straight from the leaf’s base to the tip or vice versa. These veins are evenly spaced, as are their internal branches.
Plants have veins that work to distribute leaf sap and nutrients to the upper layers of the leaf. Parallel venation is when the veins in a leaf run parallel to one another, as opposed to radiating.
There are many different reasons why plants may have parallel venation. For example, plants that have many leaflets, like a maple, will have parallel venation to help ensure that the leaflet is well supplied with nutrients and water.
Parallel venation can also have some evolutionary advantages. For example, in plants like the cabbage palm, there are no veins radiating out from a single leaf vein, but instead, all of the veins radiate off of a single central vein.
This has evolved because if the leaves get damaged all of the leaves can be affected at once so instead of having to heal in their own way they work together to heal themselves as one.
Lastly, parallel venation can be a trait that is passed down in the genes. It is more efficient for nutrients to be dispersed throughout the leaves in this way and it allows for a more even distribution of nutrients and water.
Parallel Venation Examples
Which plant has parallel venation?
Banana, bamboo, wheat, grasses, and maize are few examples of the parallel venation
Parallel Venation and Reticulate Venation
Parallel venation is a type of leaf vein that runs parallel to the main axis of the leaf. Reticulate venation is a type of leaf vein that has irregular branching and often resembles a net or mesh.
Parallel venation is the most common form of venation, and it occurs when the veins are arranged in a parallel pattern. Reticulate venation is less common and typically found on leaves with an irregular shape.
The veins in reticulate venations are more difficult to trace than those in parallel venations because they branch out from one another
The main difference between them is in their appearance
Parallel Venation Leaves Diagram
Parallel venation is when the veins that branch out from the mid-rib are evenly spaced from each other and run parallel to one another. Example of the parallel venation is shown in the diagram below (picture on the left side)
Types of Parallel Venation
Parallel venation can be divided into two types: pinnately and palmately.
Pinnately Parallel Venation:
Have a prominent midrib in the middle from which several veins pass perpendicularly parallel to each other. Plants with pinnately parallel venation have banana leaves. This form of venation is also known as unicostate parallel venation.
Palmately Parallel Venation:
Several veins emerge from the tip of the petiole and run parallel to each other before meeting at the apex. In grasses, palmately parallel venation can be seen. This kind of parallel venation is also known as multicostate parallel venation.
Palmately parallel venation is further subdivided into;
- Divergent parallel venation
- Convergent parallel venation
When veins emerge from the midrib, run parallel to the midrib, and unite at the leaf’s apex, the condition is known as convergent parallel venation. The leaf is divided into lobes in divergent parallel venation, and a vein reaches each lobe separately; palmyra palm is a good example.