Morchella frustrata is a species of fungus in the family Morchellaceae native to North America, commonly referred to as the mountain blond or western blond morel. It has conical, yellowish to tan fruit bodies that grow up to 6 cm (2.4 in) tall and 4 cm (1.6 in) wide. Described as new to science in 2012, it has been collected from California and Oregon, where it occurs in mixed forests. It has also been collected in Turkey, although it is unknown if its presence there is a result of an accidental introduction.
Morchella frustrata was described as new to science in a 2012 publication by Michael Kuo and colleagues. The report resulted from the Morel Data Collection Project, which aimed to clarify aspects of the biology, taxonomy and distribution of North American Morchella, and described 14 new morel species. The type locality was in Placer County, California. The morel was previously referred to as phylogenetic species (i.e., defined by DNA sequence rather than morphological characteristics) Mel-2 in a study the year before, and informally as the "mountain blond morel". Despite its light color, M. frustrata is in the elata clade along with other black morels, including M. tomentosa and M. angusticeps. The specific epithet frustrata refers to the "frustrating combination of black and yellow morel features that characterize the species."
The fruit bodies are 6–9 cm (2.4–3.5 in) high. The conical cap is 4–6 cm (1.6–2.4 in) high and 2.5–4 cm (1.0–1.6 in) 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 ridges are initially colored pale yellowish to nearly whitish when young, but turn pale tan in age. They are slightly flattened when young but often become sharpened or eroded. 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 2–4 cm (0.8–1.6 in) high by 1–2.5 cm (0.4–1.0 in) 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; near the base of the stipe the flesh is sometimes slightly chambered. The sterile inner surface of the cap is whitish and pubescent (having soft, short and erect "hairs").
The ascospores are smooth, elliptical, and measure 20–29 by 14–19 µm. Asci (spore-bearing cells) are cylindrical, eight-spored, hyaline (translucent) when mounted in dilute (2%) potassium hydroxide (KOH), and measure 225–300 by 15–25 µm. Paraphyses are cylindrical, measuring 100–225 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 100–175 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.
Due to its similar light coloration, M. frustrata may 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.
Habitat and distribution
Morchella frustrata fruit bodies grow singly, scattered, or in groups on the ground in spring. Although the ecological preferences of the fungus are not known with certainty, it is suspected of being both saprobic and mycorrhizal at different times in its life cycle. Tree species predominant in the mixed forests containing the fungus include pacific madrone (Arbutus menziesii), oaks (Quercus spp.), Douglas fir (Pseudotsuga menziesii), ponderosa pine (Pinus ponderosa), sugar pine (Pinus lambertiana), and white fir (Abies concolor). Kuo suggests that it might be widely distributed in western North America, but it has only been confirmed to be present in Oregon and California. Identified as phylogenetic species Mel-2, M. frustrata has also been found in Turkey, but is suspected of having been introduced there from North America.
- Kuo M. "The Morchellaceae: True Morels and Verpas". MushroomExpert.com. Retrieved 2013-12-16.
- Kuo M, Dewsbury DR, O'Donnell K, Carter MC, Rehner SA, Moore JD, Moncalvo J-M, Canfield SA, Stephenson SL, Methven AS, Volk TJ. (2012). "Taxonomic revision of true morels (Morchella) in Canada and the United States". Mycologia 104 (5): 1159–77. doi:10.3852/11-375. PMID 22495449.
- O’Donnell K, Rooney AP, Mills GL, Kuo M, Weber NS, Rehner SA. (2011). "Phylogeny and historical biogeography of true morels (Morchella) reveals an early Cretaceous origin and high continental endemism and provincialism in the Holarctic". Fungal Genetics and Biology 48 (3): 252–65. doi:10.1016/j.fgb.2010.09.006. PMID 20888422.
- Pilz D, McLain R, Alexander S, Villarreal-Ruiz L, Berch S, Wurtz TL, Parks CG, McFarlane E, Baker B, Molina R, Smith JE. (March 2007). Ecology and management of morels harvested from the forests of western North America. General Technical Report PNW-GTR-710. Portland, Oregon: U.S. Forest Service Pacific Northwest Research Station.
- Kuo M. (2005). Morels. Ann Arbor, Michigan: University of Michigan Press. p. 173. ISBN 978-0-472-03036-1.
- Kuo M. (November 2012). "Morchella frustrata". MushroomExpert.com. Retrieved 2013-12-15.
- Taşkın H, Büyükalaca S, Hansen K, O’Donnell K. (2012). "Multilocus phylogenetics analysis of true morels (Morchella) reveals high levels of endemics in Turkey relative to other regions of Europe". Mycologia 104 (2): 446–61. doi:10.3852/11-180. PMID 22123659.
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