I mentioned that it is important to avoid excessive digging because that disrupts the mychorrhizal network, and you can see why. However, occasional digging in a small area to plant something new is not going to do much damage.
Wikipedia has an excellent discussion of mychorrhizal fungi:
http://en.wikipedia.org/wiki/Mycorrhiza#Ectomycorrhiza. I highly recommend it for anyone interested in learning more about this important botanical function. There are literally dozens of fascinating and amazing things to learn about how plants and fungi can work together.
A few days later I was working in another part of the yard and found the mushrooms below, covered by leaf mulch. The largest ones are about the size of a quarter and they are very bizarre. I've never seen anything like them before.The caps of the mushrooms are concave, unlike most other mushrooms. They are on the north side of the house so they are in shade almost all the time.
I've been looking on the internet to try to identify this weird fungus and the most I can say at this point is that it appears to be a type of cup fungus. I will be contacting the San Diego Mycological Society (www.sdmyco.org) to see if they can help me with identification.
