Plant Biology and Classification

Taxanomy is a scince of classifying living things according to their similarities and diferences.

A basionym is the original name upon which a new name is based. In botanical nomenclature, the original name provided in a citation is the basionym.

Bentham and Hooker's system of classification is published in the book Genera Plantarum. It was published in 3 volumes from the year 1862 to 1883. It is a natural system of classification. In this book, they arranged the species according to the system. They grouped 97,205 species of flowering plants into 202 orders.

Lichens are a symbiotic partnership of fungus and algae. The dominant partner is the fungus, which gives the lichen the majority of its characteristics from its thallus shape to its fruiting bodies. So, thallus is foliose in lichens. Lichens occur in one of four basic growth forms. crustose, squamulose, foliose and fruticose. So, the correct answer is 'Lichens'.

In lichens, a relationship occurs in which the fungus lives as a dominant organism and algae like a slave, the relationship is known as helotism. It is a form of symbiosis in which one species is forced to perform tasks for another, for their mutual benefit. Thus, the correct answer is option B. 

Most lichen fungi belong to Ascomycetes. The lichen fungi cultivate partners, that manufacture food by photosynthesis. Sometimes, the partners are algae (kingdom Protista), other times cyanobacteria (kingdom Monera), formerly called as blue-green algae.

Certaria is a kind of lichen which lives in close association with green algae. It is a very good source of laxative which makes bowel movement easy and loosen the stools. Most of these species are found at high latitudes, occurring on sand and shrub lands.

Foliose lichen is a lichen thallus growth form that has a 2-dimensional, flat, leaf-like lobes and lifts up from the surface. Parmelia is a medium to large foliose lichen with ends of the leaf-like lobes often squarish-tipped.

Lichens have a symbiotic relationship. In this type of relationship, lichens live symbiotically. there is a symbiotic relationship between algae and fungi in lichens. Algae perform photosynthesis and provide with carbon compounds. Fungi provide protection and nutrition to algae. Thus, 2 organisms are involved in a lichen. 

The species of the lichen Rocella is used for the extraction of the dye which serves in the formation of litmus. The litmus papers are used for testing of the pH. The litmus paper turns blue at alkaline pH and red at acidic pH. The change in the pH can be analysed using the litmus papers. 

Reindeer moss is a type of lichen. It grows in arctic regions and is a bluish-grey organism. In winters, it provides food for reindeer. Apple moss, peat moss and club moss are typical mosses. 

Cyphella are aerating organs in the form of organised breaks, which occur in the lower cortex and appear as concave circular depression where white medulla is exposed.