Oyster Mushroom

As an edible mushroom, the oyster mushroom has been a part of many cuisine and dishes across countries. Occurs throughout Britain and Ireland as well as in most parts of mainland Europe. It is also widely distributed throughout much of Asia, including Japan, and is present in parts of North America. It is also used as medicine in treating varied ailments in ancient Chinese medicine. It is one of the most widely consumed mushrooms worldwide. China is the major producer of edible mushrooms, and also produces more than 85 percent of all oyster mushrooms (Pleurotus spp.) grown worldwide. The Oyster Mushroom was first described scientifically in 1775 by Dutch naturalist Nikolaus Joseph Freiherr von Jacquin (1727-1817) and named Agaricus ostreatus. (In the early days of fungus taxonomy most of the gilled mushrooms were included in the genus Agaricus.) In 1871 German mycologist Paul Kummer transferred the Oyster Mushroom to the genus Pleurotus (a new genus that Kummer himself had defined in 1971), giving it its currently accepted scientific name.

Podredumbre agarica del chopo (Spanish), Pleurote (French), Oesterzwam (Belgium), Austern Seitling (German), Gewone oesterzwam (Dutch), Boczniak ostrygowaty (Poland), Hira take (Japanese), Hao yun (Chinese).

Pleurotus ostreatus grows in shelf-like clusters on dead logs and living trees (primarily hardwoods, but sometimes on conifers). Commonly found on deciduous hardwoods, especially beech and aspen trees. They are rarely found on conifers as well. Can be found in forests in sub-tropical and temperate climates. Oyster mushroom can grow at moderate temperature ranging from 20 to 30 °C and humidity 55 - 70% for a period of 6 to 8 months in a year. In hilly areas above 900 m.s.l, the best growing season is during March/April to September/October and in the lower region from September/October to March/April.

• Mycelium - kind of like the "roots" of the mushroom. 
• Stem - usually rudimentary and lateral (or nearly absent) when mushrooms are growing from the sides of logs or trees, but sometimes more or less central when growing on the tops of logs or branches; 1–7 x 1–3 cm; whitish; hairy to velvety; tough.
• Gills - crowded, decurrent, running down the stem (or pseudostem); close; short-gills frequent; whitish or with a grey tinge, becoming yellowish in age and sometimes developing brownish edges.
• Spore - subcylindrical to narrowly kidney-shaped, smooth, 8-12.5 x 3-4.5µm. Spore print: using a dark background, it will appear white or lilac-grey.
• Cap - 5–25 cm across; broadly convex, becoming flat or shallowly depressed; kidney-shaped to fan-shaped in outline, or nearly round if growing on the tops of logs; somewhat greasy when young and fresh; bald; pale to dark brown; fading to buff; sometimes fading slowly and becoming two-toned; the margin somewhat inrolled when young.

Reproduces by spores, and the vegetative growth is by mushroom spawn which is simply any substance that has been inoculated with mycelium. Any material with mycelial growth used to propagate mushrooms is considered 'spawn'. The spawn is used to transfer mycelium onto any material from which mushrooms will grow, called a substrate. The spawn comes in one of these forms: sawdust, grain, plug/dowel, woodchip, straw, and liquid (water enriched with mushroom spores).

β-glucans, mevinolin (known as lovastatin), essential amino acids (threonine, valine, isoleucine, leucine, histidine), lignin, and phenolic compounds.

• Oyster mushroom is used in Chinese medicine in aiding varied conditions, include atherosclerosis, diabetes, high cholesterol, and respiratory tract infections.
• It is able to lower cholesterol level, which leads to lesser risks of possible several heart diseases and liver.
• It can reduce the risks of cancer.
• Enhances the immune system, making one less susceptible to viral infections such as flu and colds.