Question

Name two examples of heterosporous pteridophytes.

Answer 1

Hint: Pteridophytes are the only vascular in subdivision cryptogame. It also bears seed but fruits and flowers don’t form. The homosporous plants consist of a spore of a similar type whereas heterosporous plants consist of a spore of a different type.

Complete Answer:
Selaginella and Salvinia are two examples of heterosporous pteridophytes. These pteridophytes consist of two types of spores, large spores that germinate to produce female gametophyte and small spores germinate to produce male gametes.

Additional information:
Selaginella comes under class lycopsida which is also known as club moss. Selaginella consists of different types of species, in which maximum species found in the tropical rainforest and some species found in a dry habitat, species of dry habitat rolls up in form of a ball and when they get in contact with water by rain balls get open into normal form, therefore, Selaginella is also known as evergreen pteridophyte. The plant body is perennial, herbaceous, with the presence of stem, leaves, and root. They do not produce a leaf gap in the stem strand. Vegetative reproduction takes place by fragmentation, bulbils, and tubers. Strobili plants bear two types of sporangia, megasporangia, and microsporangia. Microspore consists of antheridium and megaspore consists of the archegonium. Fertilization requires water after the formation of sperm and egg. Cross-fertilization takes place between egg and sperm which leads to the formation of zygote with upper suspensor cell and lower basal cell.
Salvinia comes under class pteropsida which is the largest group of plants and called ferns. Salvinia is a floating fern therefore also known as water moss. They have an underground stem called rhizome with adventitious root and aerial leaves with sporangia and sori. Vegetative reproduction takes place by fragmentation, adventitious buds, and bulbils. Spore on germination produces gametophyte which is thalloid and also known as prothallus. Different types of spores are produced that is male antheridia and female archegonia. Sperm is multiciliated and reaches archegonia by the water where archegonia are flask-shaped partially embedded in prothallus.

Note: Selaginella bryopteris is sanjivani of Ayurveda and Selaginella rupestris is also known as birds nest moss. Salvinia is also called the sorrow of Kashmir because it is a type of aquatic weed. Salvinia molesta, Salvinia herzogii, and Salvinia minima are the hybrid types because their sporangia are empty and they cannot form in reproduction.