Fungus.org.uk
Title
Index - fungus.org.uk
Description
Unlike bacteria, fungi are eukaryotes (i.e. their cells contain complex organelles such as nuclei which are also found in animal and plant cells). Although some fungi may superficially resemble plants recent molecular evidence suggests that fungi are probably more closely related to animals. Most fungi grow in the form of microscopic filaments called hyphae that extend and branch at their tips to form a vast network or mycelium. The familiar field and forest mushrooms are the fruiting structures that arise from such a network. To exploit new habitats fungi have to produce countless millions of spores since very few of these spores will successfully form new colonies. With gilled mushrooms the spores are produced on the surface of the gills. These delicate structures serve to increase the surface area available for the production of spores and are protected by the more robust cap. The presence or absence of a volva and ring are important characteristics used for identifying these types of fungi. Some species have pores, spines or blunt ridges instead of gills. However, the reproductive structures of many fungi do not have the characteristic mushroom shape at all and range in size from the giant puffball to the tiny conidiogenous structures of moulds.
The larger fungi are divided into two main groups (phyla) based on the way that they produce their spores. The Ascomycota produce their spores inside a long cell called an ascus. The Basidiomycota form their spores externally on a club-like cell called a basidium.
Fungi play a vital role in nature. Many are saprotrophs, living on dead organic matter such as leaf litter and have an important role in re-cycling. Others form symbiotic associations with trees and other plants (mycorrhizal fungi) which extend the plant root system assisting in the uptake of water and nutrients. Over 90% of plants have a fungus associated with their roots and many would not survive without their fungal partner. It has also been estimated that over 1000 species of insects and other creatures in the UK alone are dependent on fungi for food and shelter.
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