These mushrooms, one of the groups of mushrooms commonly known as ink-caps, are all over the garden now. They are actually edible, but taste like nothing. They also must not be eaten when festivities are in the planning, because they contain a substance that encourages vomiting and accelerated heart rates when taken with alcohol. Once you pick them, they will quickly turn black (hence the name). You should try to cook them before they do, as they then begin disintegrating into a mush.
The name Japanese Parasol is derived from the graceful shape of the cap. Incidentally,they sometimes turn outward like an umbrella in the wind. From the ground, they resemble a head of garlic.