Spores 



r Germinating 

 V spores 



are produced by mycor- 

 rhizal fungi. These 

 include representatives 

 within the class Basidio- 

 mycetes (mushrooms), 

 which includes the gen- 

 era Cantharellus 

 (chanterelles), Boletus 

 (Boletes), Lactarius 

 (milky caps), Tricholoma 

 (matsutake), Hydnum 

 (tooth fungi), and Ramar- 

 ia (coral fungi) (Molina 

 and others 1993). Edible 

 fungal fruiting bodies also 

 are produced by the 

 class Ascomycetes (cup- 

 fungi), represented by 

 Morchella (morels) and 

 the mycorrhizal Tu- 

 ibera/es (truffles). 



Plants can have many 

 mycorrhizal associates; 

 trees are believed to 

 have more than other 

 plant groups. Douglas- 

 fir {Psuedotsuga menziesii (Mirb.) Franco) is known to have nearly 2,000 fungal 

 species (Trappe 1977). Mycorrhizal fungi rely on the presence of their host, and will 

 die with their host. Harvesting or fire can result in a short-term disappearance of these 

 fungi, but they recolonize when trees again become established. Trees that are hosts 

 to mycorrhizal fungi in the Pacific Northwest include those mainly in the families Pi- 

 naceae, Fagaceae, Betulaceae, Salicaceae, and a few Ericaceae (Molina and others 

 1993). ,--^ 



Young 

 mushroom 



Fruiting body development 



Figure 7 — Life cycle of a typical mushroom (basidiomycetes). (As modified 

 from page 64 of Stamets 1994.) 



Reproduction 



Specific reproductive processes are different for different species and groups of fungi. Af- 

 ter spores are dispersed and germinate, they form haploid (monokaryote) vegetative 

 hyphal strands (mycelium) through their adapted substrate. Sexual reproduction can occur 

 when two compatible mating types grow together and fuse, and dikaryotic or binuculeate 

 mycelium develops. When conditions are correct, the sexual stage is initiated and mush- 

 room primordia develop. Primordia eventually develop into the fruiting structures where the 

 final process of meiosis takes place and spores are again produced. 



Mushrooms and cup-fungi are reproductive structures of individual fungal organisms that 

 are primarily large networks of filamentous microscopic cells (hyphae) in soil, in wood, or 

 on plants. Masses of hyphae (mycelium) are actually the vast bulk of the fungus. Because 

 mycelium is either hidden or not visible to the naked eye, its importance often is overlooked 

 relative to the apparent mushroom and cup-fungus fruiting structures. In actuality, the 

 mycelium network functions throughout the year, whereas the mushroom or cup-fungus is 

 produced for only a few weeks. Picking the mushroom does not alter the individual in the 

 soil (or other substrate) but is analogous to picking fruit from a tree. 



