Question

Which of the following venations is the characteristic of fern?
A.Parallel
B.Reticulate
C.Dichotomous
D.Open furcate

Answer 1

The vascular plant stem consists of principal lateral appendages known as the leaves. These are specialized in the process of photosynthesis. Foliage is a term used to refer to leaves collectively. Leaves are equipped with different textures, sizes, and shapes. Flowering plants comprise broad, flat leaves that have complex venation present on them. These leaves are known as megaphylls.

Complete answer:
Venation is defined as the arrangement of veins and veinlets in the tissues of leaves. These veins are composed of phloem and xylem cells surrounded by cells of bundle sheath embedded in the parenchyma and sometimes sclerenchyma. The veins conduct water and organic nutrients through xylem and, through the phloem, they transport carbohydrates (sugar) to the rest of the plant from the leaf.
Veins are classified based on their arrangements into reticulate, parallel, dichotomous, and furcate. Reticulate venation involves the network-like or web-like arrangement of veins over the lamina of the leaf. Some examples of plants that have reticulate leaf include China rose, hibiscus, tulsi leaf, papaya, coriander, Mangifera, etc. Parallel venation involves the parallel arrangement of veins to one another all over the lamina. Examples of plants that consist of leaves with parallel venation include grass, Oryza, maize, grains, etc. Furcate venation of leaves involves the veins to be arranged in a forked manner and the branches thus formed do not join to form a network.
Ferns are a class of non-flowering vascular plants. They possess true stems, roots, complex leaves, and reproduce through spores. The majority of the Earth’s warm and damp areas are inhabited by ferns. Only a few are found in cold, dry places.
The veins of fern leaf involve furcate venation of arrangement, i.e. veins are arranged in a fork-like manner. If the branched veins do not join each other towards the leaflet margin then it is known as open furcate venation. Whereas, if the branched veins join each other towards the leaflet tips then it is called close furcate venation.
Hence, the answer is option D. Open furcate.

Note: It has been estimated that around 15,000 species of ferns exist, but only 10,500 species of extant fern is known. Some fern species are considered to be as old as the Carboniferous Periods which is about 358.9 million years ago.