Dryopteris

Dryopteris, commonly known as the Male Fern or Wood Ferns, is a genus of nearly 250 species of ferns belonging to the family of Dryopteridaceae. These ferns are found inhabiting the temperate Northern Hemisphere, with the most species diversity seen in Eastern Asia. Most species possess stout, slowly creeping rootstocks forming a crown consisting of a ring of fronds resembling a vase-shape. The round sori of these ferns feature a peltate indusium, and the stripes possess salient scales.

Dryopteris is a genus of plants that have horizontal roots, known as rhizomes, which thrive in soil. The leaves of these plants project upwards and are referred to as fronds. These fronds are triangular in shape and have branches on either side of the stem with several small oblong leaflets. The emerging frond spouts are referred to as fiddleheads, as they resemble the head of a violin.

Dryopteris - Structure

The plant body of the sporophyte can be divided into roots, leaves, and the stem (rhizomatous).

Root

They possess branched and small roots. These roots have an ephemeral primary root which is replaced by many adventitious roots emerging from the bases of the leaves. The outer layer has a central stele and a cortex, wherein they can be distinguished into an inner sclerenchymatous and outer parenchymatous zone. Steles are diarch xylem and protostelic with exarch.

Rhizome

The rhizome of the plant has an outer one-layered epidermis, a parenchymatous cortex, and a centrally oriented dictyostelium vascular bundle with several meristeles. It is partially erect and partially horizontal, with the apex projecting above the surface of the soil. Additionally, the rhizome has thick, brown sclerenchymatous hypodermis, and scales with adventitious roots.

The meristeles are oriented in the form of rings, with leaf gaps. Each of the meristele is elliptical or round where the mesarch xylem is engirdled by phloem. Stele is bound by endodermis of 2 layers where the exterior layer is distinguishable and the interior layer unites with the pericycle of 1-2 layers. A few vessels and Tracheids constitute xylem produced due to dissolution of the end walls of the tracheids.

Leaf

Acropetal leaves can be found at the apex of the rhizome. When young, these leaves appear to be coiled in a spiral shape, exhibiting a circinate ptyxis, which is a characteristic of true ferns. The fronds are uni-pinnately compound and have a long rachis. As the old leaves wither away, the leaf bases remain.

Sori are seen on the abaxial pinnae surface of the fertile leaves, and the base of the rachis is covered by brown scales known as ramenta.

Production of Spores

The life cycle of ferns begins with the spore. Each frond on its underside has dark and tiny spots known as sori which contain sporangia - growths that produce and release spores.

Gametophyte

The spores which fall to the ground have the potential to germinate and grow into a gametophyte. This gametophyte then develops a leaf-like structure which attaches to the ground through rhizoids.

Reproductive Structures

On maturity, the gametophyte gives rise to the sex structures, with the male organs known as the antheridia and the female structures referred to as the archegonia. Both of these structures originate from the base of the gametophyte.

Reproduction through Sexual Reproduction

The male structures, antheridia, produce flagellated sperms which swim across the film of the water to reach the archegonia. Then the sperm goes into fertilizing the egg present in each of the archegonium.

Zygote is the initial cell formed when two gametes fuse during fertilization.

The process of fertilization produces a zygote, which grows from the inside of the gametophyte. The rhizomes grow underneath the soil, while the fiddleheads sprout, projecting from the rhizome and forming sporophytes.

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