Morchella esculenta

Appearance

The pitted yellow-brown caps measure 2–7 cm broad by 2–10 cm 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 2–9 cm long by 2–5 cm 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.

The cap is pale brownish cream, yellow to tan or pale brown to grayish brown. The edges of the ridges are usually not darker than the pits, and somewhat oval in outline, sometimes bluntly cone-shaped with a rounded top or more elongate. Caps are hollow, and attached to the stem at the lower edge, and typically about 2–7 cm broad by 2–10 cm tall. The flesh is brittle. The stem is white to pallid or pale yellow, hollow, and straight or with a club-shaped or bulbous base. It is finely granular overall, somewhat ridged, generally about 2–9 cm long by 2–5 cm thick. In age it may have brownish stains near the base.The spores range from white to cream to slightly yellow in deposit, although a spore print may be difficult to obtain given the shape of the fruit body. The spores are formed in asci lining the pits—the ridges are sterile. They are ellipsoidal, smooth, thin-walled, translucent , and measure 17.5–21.9 by 8.8–11.0 µm. The asci are eight-spored, 223–300 by 19–20 µm, cylindrical, and hyaline. The paraphyses are filamentous, cylindrical, 5.8–8.8 µm wide, and hyaline.

The hyphae of the stem are interwoven, hyaline, and measure 5.8–9.4 µm wide. The surface hyphae are inflated, spherical to pear-shaped, 22–44 µm wide, covered by a network of interwoven hyphae 11–16.8 µm wide with recurved cylindrical hyphal ends.

Naming

The fungus was originally named ''Phallus esculentus'' by Carl Linnaeus in his ''Species Plantarum'' , and given its current name by Swedish mycologist Elias Magnus Fries in 1801.

''Morchella esculenta'' is commonly known by various names: morel, common morel, true morel, morel mushroom, yellow morel, sponge morel, Molly Moocher, haystack, and dryland fish. In Nepal it is known as ''Guchi chyau''. The specific epithet is derived from the Latin ''esculenta'', meaning "edible".

The scientific name ''Morchella esculenta'' has been applied to many similar yellow morels throughout the world. In 2014 Richard et al. used DNA analysis to restrict the ''M. esculenta'' name to a single species of yellow morel commonly found in Europe and also reported from China. Other species of yellow morel, including those in North America, have received new scientific names.''Morchella esculenta'' is probably the most popular of the morels. In contrast to ''M. angusticeps'' and its relatives, the caps are light-colored throughout development, especially the ridges, which remain paler than the pits. ''M. crassipes'' is sometimes confused with ''M. esculenta''. According to Smith , the two are distinct, but young forms of ''M. crassipes'' are difficult to separate from ''M. esculenta''. The two are similar in color, but ''M. crassipes'' is larger, often has thin ridges, and sometimes has a stem base that is enlarged and longitudinally grooved.

Morels have also been confused with stinkhorns, but specimens of the latter have a volva at the base of the stem, are covered with gleba—a slimy, foul-smelling spore mass.

Distribution

Fruit bodies are sometimes found solitary, but more often in groups, on the ground in a variety of habitats. A preference for soil with a limestone base has been noted, but they have also been found in acid soils.
The mushroom is usually found in early spring, in forests, orchards, yards, gardens and sometimes in recently burned areas. In North America, it is sometimes referred to as the "May mushroom" due to its consistent fruiting in that month, but the time of fruiting varies locally, from February to July. It is typically the last morel species to fruit in locales where more than one species are found. For example, in Northern Canada and in cooler mountainous regions, morels typically do not appear until June. It has been suggested that the springtime fruiting may be due to their ability to grow at low temperatures to the exclusion of competition, a conclusion later corroborated by experiments correlating spore germination to soil temperatures.

One author suggests the acronym PETSBASH may be used to remember the trees associated with morels: pine, elm, tulip, sassafras, beech, ash, sycamore, and hickory.

In North America, it is widely distributed, but especially common in eastern North America and the Midwest. David Arora notes that "large crops can also be found around the bases of dying elms attacked by Dutch elm disease." The species has been named state mushroom of Minnesota, and was the first state mushroom of any state.

It can also be found in Brazil.

Habitat

Fruit bodies are sometimes found solitary, but more often in groups, on the ground in a variety of habitats. A preference for soil with a limestone base has been noted, but they have also been found in acid soils.
The mushroom is usually found in early spring, in forests, orchards, yards, gardens and sometimes in recently burned areas. In North America, it is sometimes referred to as the "May mushroom" due to its consistent fruiting in that month, but the time of fruiting varies locally, from February to July. It is typically the last morel species to fruit in locales where more than one species are found. For example, in Northern Canada and in cooler mountainous regions, morels typically do not appear until June. It has been suggested that the springtime fruiting may be due to their ability to grow at low temperatures to the exclusion of competition, a conclusion later corroborated by experiments correlating spore germination to soil temperatures.

One author suggests the acronym PETSBASH may be used to remember the trees associated with morels: pine, elm, tulip, sassafras, beech, ash, sycamore, and hickory.

In North America, it is widely distributed, but especially common in eastern North America and the Midwest. David Arora notes that "large crops can also be found around the bases of dying elms attacked by Dutch elm disease." The species has been named state mushroom of Minnesota, and was the first state mushroom of any state.

It can also be found in Brazil.