The Collaborative International Dictionary
Wikipedia
Morchella esculenta, (commonly known as common morel, morel, yellow morel, true morel, morel mushroom, and sponge morel) is a species of fungus in the Morchellaceae family of the Ascomycota. It is one of the most readily recognized of all the edible mushrooms and highly sought after. Each fruit body begins as a tightly compressed, grayish sponge with lighter ridges, and expands to form a large yellowish sponge with large pits and ridges raised on a large white stem. The pitted yellow-brown caps measure broad by tall, and are fused to the stem at its lower margin, forming a continuous hollow. The pits are rounded and irregularly arranged. The hollow stem is typically long by thick, and white to yellow. The fungus fruits under hardwoods during a short period in the spring, depending on the weather, but it is also associated with old orchards, woods, disturbed grounds and burnt areas. Although a process was reported in 1982 to grow the fruit bodies under controlled conditions, attempts to cultivate the mushroom commercially have only been partially successful.