Ancient Sanskrit literature of Bharatvarsha is a vast storehouse of knowledge of spiritual, physical, chemical and biological sciences. Shrimad Valmiki Ramayana is an epic poem (Mahakavya) of Bharatvarsha which narrates the journey of virtue to annihilate vice. Shri Rama is the Hero and aayana is His journey. It is believed that sage Valmiki wrote Ramayana ten thousand years before the birth of Lord Shri Rama. The Ramayana is composed of verses called Shloka, in Sanskrit language, which is an ancient language of India and a complex meter called Anustup. These verses are grouped into individual chapters called Sargas, wherein a specific event or intent is told. The Ramayana, originally written by sage Valmiki, consists of 24,000 shlokas and seven cantos (Kaṇḍas). But it is believed that the Uttara Kanda was not original work of Valmiki. Valmiki had written only 6 Kandas. Valmiki is celebrated as the harbinger-poet in Sanskrit literature. He is revered as Adi Kavi, the first poet, author of Ramayana, the first epic poem. Valmiki knew the flora and fauna, rivers and mountains as well and he knew the whole geography of Bharatvarsha. He has mentioned various types of forests having different kinds of plant species as found during the entire journey of Lord Rama from Ayodhya to Lanka. He has described different types of forests such tropical dry mixed deciduous forests of Tadka Vana (Malada and Karusha), Chitrakoota, Dandkaranyas (include parts of Madhya Pradesh, Chattisgarrh, and Andhra Pradesh) and Panchvati; dry and moist deciduous forest of Kishkindha and Rameshwaram and evergreen tropical forests of Sri Lanka. The author has studied entire epic Valmiki Ramayana and enumerated all plant species. The study reveals that there are about 150 plant species has been described in six Kandas. These 150 plant species belongs to 117 genera and 60 families. Fabaceae is the largest family having 16 species and Ficus, Oryza, Terminalia, Nymphaea and Jasminum are the dominant genera having 4 species each. Habit wise analysis indicates that out of these 150 species, 84 species are trees, 19 species are shrubs, 11 are climbers, 31 herbs and 5 aquatic plants. Kush (Desmostachya bipinnata), Ashok (Saraca asoca), Aam (Mangifera indica), Sal (Shorea robusta), Kamal (Nelumbo nucifera), Palash (Butea monosperma), Chandan (Santalum album), Agaru (Aquilaria malaccensis) and Rakt Chandan (Pterocapus santalinus) are frequently mentined in all six Kandas while rest plants mentined in one to five Kandas only.