Category: Biology Second Paper Lecture Sheet

Sporangia arise from the placenta or amara along the underside of the leaves of Pteris. The sporangia together form a brown kidney-shaped sorus. Each sporangium consists of two parts.
1. Pedicel or Sporangiophore: Each sporangium has a short segment at its base. It is called a stalk or sporangiophore.
2. Capsule: The upper part of sporangium is called capsule. The parts of the capsule are:
(i) Annulus: The thick covering of chitin on the capsule wall is called annulus. It is monolayer, elastic and absorbent.
(ii) Stomium: The ring in the capsule wall with a thin membrane is called stomium. It helps in spore excretion.
(iii) Spores: Inside the capsule there are sporogenous cells. 16 spore mother cells are produced from sporogenous cells. Each spore mother cell divides by meiosis to produce 4 spores. That is, 64 spores are produced from 16 spore mother cells. Spores are dark brown in color, bilayered and germpored. Spores are homosporous or homosporous.

(i) Upper layer: The upper layer of the sheet is called upper layer. It is composed of single cells. Cuticles are present on the surface.
(ii) Hypodermis: The hypodermis is composed of unicellular cells. At the bottom there are tiny sporangia along the edges. Spores are produced inside the sporangium. At the base there is a leaf pore.
(iii) Mesophyll tissue: Mesophyll tissue is present in the middle of both skins. It is composed of spongy and palisade parenchyma. Parenchyma cells contain chlorophyll and have air cavities. Its steely hydrocentric.

(i) Epidermis: The outer layer of rachis is called epidermis or epidermis. It is unilayered and composed of parenchyma cells.
(ii) Hypodermis: The inner layer of epidermis is called hypodermis or hypodermis. It is composed of sclerenchyma cells.
(iii) Cortex: The inner layer of hypodermis is called cortex. It is multi-layered. The cortex consists of horse-shaped styli or vascular bundles. Its vascular bundles are hydrocentric i.e. xylem in the center and phloem around it.

(i) Epidermis: The outer layer of the rhizome is called the epidermis. It is unilayered and composed of parenchyma cells.
(ii) Hypodermis: The inner layer of epidermis is called hypodermis or hypodermis. It is furnished on two levels. Made up of sclerenchyma cells.
(iii) Cortex: The inner layer of hypodermis is called cortex. It is multi-layered. It is composed of parenchyma cells. It does not contain intercellular spaces.
(iv) Vascular bundles: Cortex contains multiple vascular bundles. Its vascular bundles are hydrocentric i.e. xylem in the center and phloem around it.

Young leaves of ferns are called croziers. When the leaves are young, the coils are curled like a dog’s tail. This condition is called sarcinate vernation.

Fern leaves are called fronds. The leaves of Pteris are compound. Each segment of a compound leaf is called a leaf or pinna. Each leaf has one rachis. The leaves are arranged in pairs on either side of the rachis. Each leaflet is narrow, long, sessile, obtuse and the edges are smooth. Tidal pinnae are the longest. On the underside of the leaf there are tiny sporangia along the edges. The sporangia together form the sorus (spore leaf). Each sorus is covered by a false indusium. The leaves bearing the sorus are called sporophylls. Many psorai joined together to form Sinosaurus. Young leaves of ferns are called croziers. When the leaves are young, the coils are curled like a dog’s tail. This condition is called sarcinate vernation. Leaves are green and produce food through the process of photosynthesis.

The stem of Pteris is rhizome-like. Rhizomes are short, hard, firm, erect, unbranched and colorless. Its growth is indeterminate and perennial. It is located several centimeters deep in the soil. The stem is covered with numerous brown scales. These bills are called ramentum. Ramentums are green at first, later turning pink.

A narrow, thread-shaped, branched, colorless and multicellular root arises from the lower part of the stem. It is localized and clustered. Roots anchor the plant to the soil and absorb water and mineral salts.

1. Root: A narrow, thread-shaped, branched, colorless and multicellular root arises from the lower part of the stem. It is localized and clustered. Roots anchor the plant to the soil and absorb water and mineral salts.
2. Steam: The stem of Pteris is rhizome-like. Rhizomes are short, hard, firm, erect, unbranched and colorless. Its growth is indeterminate and perennial. It is located several centimeters deep in the soil. The stem is covered with numerous brown scales. These bills are called ramentum. Ramentums are green at first, later turning pink.
3. Leaf: Fern leaves are called fronds. The leaves of Pteris are compound. Each segment of a compound leaf is called a leaf or pinna. Each leaf has one rachis. The leaves are arranged in pairs on either side of the rachis. Each leaflet is narrow, long, sessile, obtuse and the edges are smooth. Tidal pinnae are the longest. On the underside of the leaf there are tiny sporangia along the edges. The sporangia together form the sorus (spore leaf). Each sorus is covered by a false indusium. The leaves bearing the sorus are called sporophylls. Many psorai joined together to form Sinosaurus. Young leaves of ferns are called croziers. When the leaves are young, the coils are curled like a dog’s tail. This condition is called sarcinate vernation. Leaves are green and produce food through the process of photosynthesis.

1. Plants are divided into roots, stems and leaves.
2. Plant stems are transformed into rhizomes and covered with ramenta.
3. From the rhizomes slender, linear, apical and branched roots emerge. It is covered by ramenta.
4. Leaves are compound, young leaves have circinate vernation.
5. The leaves are attached to the rachis. Leaves have midveins and veins.
6. At the edge of the leaf, the sporangia are united to form a sorus. It is covered by phallus indusium.