Physcia
General structure Physcia is foliose lichen. Physcia is divided into four regions internally. These regions are: 1. Upper cortex: It is present at the upper regions. It is composed of closely packed hyphae. Spaces are absent between them. If spaces are present, they are filled by gelatinous material. The upper surface may be smooth or it […]
Agaricus
This is a large genus of fungi often synonymized with the term ‘mushrooms’, distributed mainly in temperate regions. Agaricus spp. are saprotrophs, growing in pastures and woodland litter. The mycelium is perennial and some species and some species, e.g. A. arvensis (horse mushroom), A. xanthodermus (yellow stainer) and A. tabularis may fruit in rings. From measurements […]
Yeast Bread-making
The principle behind the leavening of bread dough by baker’s yeast is the same as in brewing, i.e. the anaerobic metabolism of glucose and other reducing sugars via pyruvic acid into ethanol and CO2. The difference is that the released CO2 is the important product in breadmaking because it is responsible for the texture of […]
Ascomycota Fruit Bodies
Types of fruit body: There are number of fruit bodies in Ascomycota. In yeasts and related fungi the asci are not enclosed by hyphae, but in most ascomycetes they are surrounded by hyphae to form an ascocarp or ascoma. An old term for ascus is theca (Gr. theca=a case), and although this word is not now in general […]
Pythium
Species of Pythium grow in water and soil as saprotrophs, but under suitable conditions, e.g. where seedlings are grown crowded together in poorly drained soil, they can become parasitic, causing diseases such as pre-emergence killing, damping off and foot rot. Damping off of cress (Lepidium sativum) can be demonstrated by sowing seeds densely on heavy […]
Zygomycetes Mucorales
In most members of the Mucorales, numerous spores are contained in globose sporangia borne at the tips of aerial sporangiophores. Within the sporangium the spores may surround a central core or columella, although in some species the columella is greatly reduced. Some species possess fewspored sporangia, termed sporangiola, which are often dispersed as a unit, […]
Taxonomy of fungi
Taxonomy is the science of classification, i.e. the ‘assigning of objects to defined categories’. Classification has three main functions: it provides a framework of recognizable features by which an organism under examination can be identified; it is an attempt to group together organisms that are related to each other; and it assists in the retrieval […]
Cleavage of ascospores
In many ascomycetes, studies of the fine structure of asci during cleavage of the ascospores have shown that a system of double membranes continuous with the endoplasmic reticulum extends from the envelope of the diploid fusion nucleus. The double membrane develops to form a cylindrical envelope lining the young ascus. This peripheral membrane cylinder or […]
Ascus development in Ascomycota
In yeasts and related fungi, the ascus arises directly from a single cell, but in most other ascomycetes it develops from a specialized hypha, the ascogenous hypha, which in turn develops from an ascogonium. Ascogenous hypha The ascogenous hypha of many ascomycetes is multinucleate, and its tip is recurved to form a crozier (shepherd’s crook). […]
Dolipore septum
The transverse septa which divide both monokaryotic and dikaryotic hyphae into segments are incomplete; they contain a central pore which permits cytoplasmic continuity between adjacent segments. The septal pore is surrounded by a barrel-shaped flange of thickened wall material. Such septa, which are characteristic of basidiomycete mycelia, are known as dolipore septa (Lat. dolium= large […]