In the stem of monocot there exist three tissue systems —dermal, vascular and ground tissues, which consist of epidermis, vascular bundles and all tissues except the former two respectively. A brief account of the arrangement and structure is given below. Epidermis: Epidermis is more or less like dicots. In contrast to dicot stem, the epidermis is usually devoid of glandular [...]
On the basis of internal structure of thallus, the lichens are divided into two groups, namely, homoiomerous and heteromerous lichens. 1. Structure of Homoiomerous Lichen Thallus: In the gelatinous lichen thalli such as Collema and Leptogium, the thallus shows a simple structure with little differentiation. It consists of a loosely interwoven mass of fungal hyphae with algal cells equally distributed [...]
In this article we will discuss about the economic importance of lichens. 1. Certain species of lichens are valuable sources of food. Most important of these are the fruticose lichen Cladonia rangiferina (Reindeer Moss) and other tundra lichens which serve as food for reindeer, caribou, musk ox and other wild animals of the Arctic tundra zone. A few species have [...]