parasol mushroom Macrolepiota (or Lepiota) procera, a large, shaggy fungus, among the finest of edible mushrooms. The specific name procera means tall; a really large specimen may stand up to 30 cm (1') high and measure 25 cm (10") across the cap, which is shaped like a Chinese umbrella with a projecting boss in the middle. The gills are white or off-white. The stem bears a large, double ring but has no volva (torn sheath) at its base. It has a feltlike grey-brown covering which splits into vertical streaks as the stem expands. The cap is buff or grey-brown and scaly.