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 [...]
The following points highlight the four main types of lichen thallus. The types are: 1. Crustose (Crustaceous) Lichens 2. Foliose (Foliaceous) Lichens 3. Fruticose Lichens 4. Squamulose Lichens. Type # 1. Crustose (Crustaceous) Lichens: The thallus is of insignificant size. It is flat, thin usually without any distinct lobes. It is just like a thin layer or crust closely attached [...]
The following points highlight the two main examples of lichens. The examples are: 1. Parmelia 2. Usnea. Example # 1. Parmelia: It is a common example of a foliose lichen which is found growing on the bark as well as the rock intermixed with the mosses at higher altitude (above 4,000 ft.). The heteromerous thallus is lobed to deeply incised. [...]