Common Names: 'Yellow Morel,' 'Morel,' 'Sponge Mushroom,' 'Gray Morels,' 'Brain Mushrooms,' Scientific Names: Morchella esculenta, Morchella deliciosa. The yellow morel is probably the most prized of all edible mushrooms. Its flavor is delicate, and its texture is meaty. Yellow morels range from minuscule to enormous--up to nearly a foot high. They follow the black morels, usually reaching the peak of their fruiting season. Though they are usually yellow, yellowish brown, or honey brown, they are sometimes grayish or even whitish--especially when tiny and fresh, or when covered by leaves. They are hollow, of course, and their stems are white. In some varieties, the stem is enlarged towards the base, especially late in the season, and when this is the case there may be several flaky layers of flesh in the base of the stem.
They are 'pitted,' or 'honeycombed.' When young the ridges may be almost white and the pits nearly black. At maturity, they are nearly uniformly yellowish brown, though the pits are still darker than the ridges. Some mycologists regard Morchella esculenta and Morchella deliciosa as two separate species. M. deliciosa is distinguished by being smaller, pointier, and involving pits that are prominently vertically arranged. Adjacent picture illustrates the two species side by side