(recycled from 5/17/2011)
Mushrooms have been used as medicine for millennia. Their DNA most closely resembles human DNA (as opposed to a plants DNA), lending them a strong biological and sometimes also a mythical link. Mushrooms will pop up above and below ground and can have stems or simply manifest as a puffball mushroom sans stem (used to staunch bleeding in Native American medicine or for sore throat in Chinese Medicine, they are known as Ma Bo).
From the Chinese medicinal cooking perspective, mushrooms (all types) have a wide and incredible healing capacity. They are cool and sweet in nature; decrease lipid (fat) levels in the blood; treat liver disorders (hepatitis, cirrhosis, liver cancer, or general liver toxicity); treat excess phlegm (in cases of congestion in the lungs); increase immunity (some are stronger than others, the Ling Zhi variety fares best for this); help to reduce tumors; and promote appetite (again, think cancer and a decreased appetite here).
Morels (Morchella esculenta) have been shown in particular to increase immune function in humans. They tend to grow around white ash or elm tree's and will show their faces sometime in the Spring, anywhere from April to early June, depending on where you are in the world and if they happen to grow there. If you are lucky enough to be where they are, you can find them in farmers markets where savvy mushroom foragers will share their bounty. They are only found growing wild and have not been cultivated to date (much like truffles). Though there aren't many mimics of morels, when foraging for them and any mushroom, you should always beware as a poisonous mushroom can not only make you very sick but can also kill you.
The most common morels are the yellow (M. esculenta), white (M. deliciosa), and black morels (M. elata). You may also find the half free or spike morel (M. semilibera) earlier in the season. Often morels live in symbiosis with the trees they grow by where they will provide the tree with water and the tree in turn will provide sugar which the morel will feed on. Their appearance in the Spring in conjunction with their immunity boosting capabilities after a long winter is yet another perfect example of how eating medicinally goes hand in hand with eating seasonally.
(spike morel, usually shows up before yellow and black morels)