Botany with Rohit Jirobe

  Lichens: Characteristics, Types, Structure Lichens are group of organisms of composite nature, having two dissimilar organisms (algae and fungus) bounded in a symbiotic relationship. Algae or  cyanobacteria  and fungus forms beneficial symbiotic relationship to form lichen. The algal component is called phycobiont and the fungal component is called mycobiont. The algal component is usually green-algae (chlorophyta) or blue-green algae (Cyanophyta). Usually the fungal component is formed by Basidiomycetes or Ascomycetes. Lichens The fungal partner occupies the major portion of the thallus and produces its own reproductive structures. The algal partner manufactures the food through  photosynthesis  which probably diffuses out and is absorbed by the fungal partner. About 400 genera and 15,000 species of lichen are found all over the world. General Characteristics of Lichens Lichens are the group of plants having composite thalloid structure consisting of algae an...

  Sargassum: Occurrence, Features and Reproduction Occurrence of  Sargassum: The genus Sargassum ( Spanish sargazo , sea­weed) is represented by about 150 species, out of which 1 6 species are found in India . It is found in tem­perate, subtropical and tropical regions of both northern and southern hemispheres. It is very common in Africa, South America, Australia etc. In West Africa, a part of Atlantic Ocean becomes densely occupied by Sargassum and the region is called as ‘ Sargasso sea ’. Sargassum filipendula , a free-floating large kelp found in the Sargasso Sea, was discovered by Columbus in 1492, as the ships were held fast by the sea weeds. In India it is found in Porbandar, Bombay, Okha, Lakshadweep Island etc. Plant Body of  Sargassum : The plant body is diploid (2n), erect and branched thallus (Fig. 3.116). The thallus is differentiated into a basal holdfast and an expanded, leafy, cylindrical main axis. The holdfast is discoid and serves the func­tion of anc...

 🌐 VIRTUAL HERBARIUM & E-FLORAS DOCUMENTATION (B.Sc. Botany – 3rd Semester Notes) With the advancement of technology, traditional herbaria and printed floras are now being converted into digital platforms . A Virtual Herbarium and e-Flora are modern tools used for studying plants using online databases, digital images, high-resolution photographs, and computer-based identification systems . These digital systems make taxonomic information easily accessible to students, researchers, teachers, environmentalists, and plant taxonomists across the world . 💻 VIRTUAL HERBARIUM 📌 Definition A virtual herbarium is a computer-based digital collection of herbarium specimens , scanned and stored online with detailed plant information. It is simply a digital version of a real herbarium , available on the internet. 📌 Features of Virtual Herbarium High-resolution scanned images of herbarium sheets Online database with scientific information Search system for family, genu...