C. Mycorrhizae form when fungi enter into mutualistic interactions with tree roots, which benefit greatly from the fungus's ability to absorb needed nutrients. D. Collectors have seen a decline in populations of wild mushrooms since the early 1900s, most probably due to the increased levels of pollutants in the air. I. Characteristics of Fungi A. Mode of Nutrition 1. Fungi are heterotrophs that utilize organic matter. Saprobes get their nutrients from nonliving matter.
Parasites thrive on tissues in living hosts.
All fungi rely on extracellular enzymatic digestion and absorption. Fungi are valuable decomposers in the environment. B. Major Groups 1. Over 56,000 species of fungi have been identified and there are many more. About 430 million years ago fungi started invading the land.