Morchella frustrata

Appearance

The fruit bodies are often rufescent and 9–20 cm high. The conical cap is 4–6 cm high and 2.5–4 cm wide at the widest point. The cap surface features pits and ridges, which are formed from the intersection of 16–22 primary vertical ridges and few shorter, secondary vertical ridges, with frequent, sunken, horizontal ridges. The cap is attached to the stipe with a distinct sinus about 2–4 mm deep and 2–4 mm wide. The smooth, splitting ridges remain persistently pale throughout the maturity process, easily distinguishing this species from other species in section Elata, or black morels, which have ridges that typically darken with age. Pits are usually elongated vertically. They are smooth, dull grayish to pale yellowish or nearly whitish when young, later becoming pale tan to pale pinkish tan. The stipe is 2–6 cm high by 1–4 cm wide and is more or less equal in width throughout its length or sometimes thicker at the base. Its whitish surface is smooth or finely mealy with whitish granules. The flesh is whitish and measures 1–2 mm thick in the hollow cap. The sterile inner surface of the cap is whitish and pubescent .



The ascospores are smooth, elliptical, and measure 20–26 by 13–18 µm. Asci are cylindrical, eight-spored, hyaline when mounted in dilute potassium hydroxide , and measure 225–330 by 15–25 µm. Paraphyses are cylindrical to capitate or moniliform, measuring 95–250 long by 10–25 µm wide, and are septate. Their tips are rounded to somewhat club-shaped or infrequently somewhat fuse-shaped. Elements on the sterile ridges are 50–175 by 12.5–20 µm, and septate. The terminal cells are club-shaped or nearly so.

Although the edibility of ''M. frustrata'' was not mentioned in the original description, Kuo has elsewhere written of the edibility of North American ''Morchella''. In general, morels should not be eaten raw, as they can trigger allergic reactions in susceptible individuals. Their flavor is enhanced after they are fried, stuffed, or dried.

Naming

This species is very similar to ''Morchella rufobrunnea'', another rufescent, cosmopolitan species with pale colours, which is nonetheless found in urban and suburban areas. The latter is distinguished by an adnate cap lacking a sinus and a distinct dark pruinescence on the stem, more pronounced in young fruit bodies. Due to its similar light coloration, ''M. frustrata'' may also be confused with ''Morchella esculentoides''; as Kuo states, "it looks like a black morel with the colors of a yellow morel." The vertically arranged pits and ridges, as well as the slight indentation where the cap meets the stem on ''M. frustrata'', however, more closely resemble the black morels such as ''M. elata''. ''M. snyderi'' is somewhat similar in appearance to young specimens of ''M. frustrata'', but mature specimens of the former species can be distinguished by the brown to black ridges on the cap, and the ridged and pocketed stipe.

Distribution

''Morchella frustrata'' fruit bodies grow solitary, scattered, or in small groups in spring, in mountainous forests and maquis. The exact trophic status of the fungus is not yet known with certainty, but it is suspected to be fucaltitive mycorrhizal or biotrophic. Tree species associated with the fungus include pacific madrone , oaks , Douglas fir , ponderosa pine , sugar pine , and white fir . In Europe it is often found with holm oak , strawberry trees , olive trees , Spanish fir , Silver fir and Scot's pine . Although it was originally hypothesized that collections of ''M. frustrata'' from Turkey might have been recently introduced from North America, numerous collections reported since from remote and undisturbed areas in the Mediterranean and the Alps , suggest a long-time and well-established presence of this species in Europe. Kuo suggests that it might be also widely distributed in western North America, but so far has only been confirmed to be present in Oregon and California.

Habitat

''Morchella frustrata'' fruit bodies grow solitary, scattered, or in small groups in spring, in mountainous forests and maquis. The exact trophic status of the fungus is not yet known with certainty, but it is suspected to be fucaltitive mycorrhizal or biotrophic. Tree species associated with the fungus include pacific madrone , oaks , Douglas fir , ponderosa pine , sugar pine , and white fir . In Europe it is often found with holm oak , strawberry trees , olive trees , Spanish fir , Silver fir and Scot's pine . Although it was originally hypothesized that collections of ''M. frustrata'' from Turkey might have been recently introduced from North America, numerous collections reported since from remote and undisturbed areas in the Mediterranean and the Alps , suggest a long-time and well-established presence of this species in Europe. Kuo suggests that it might be also widely distributed in western North America, but so far has only been confirmed to be present in Oregon and California.