Early false morel

Appearance

The cap of this fungus is 2 to 4 cm in diameter by 2 to 5 cm long, with a conical or bell shape. It is folded into longitudinal ridges that often fuse together in a vein-like network. The cap is attached to the stem at the top only—hanging from the top of the stipe, with the lobed edge free from the stem—and varies in color from yellowish brown to reddish brown; the underside of the cap is pale. The stem is 6 to 12 cm long by 1 to 2.5 cm thick, cream-white in color, and tapers upward so that the stem is thicker at the base than at the top. Although the stem is initially loosely stuffed with cottony hyphae, it eventually becomes hollow in maturity; overall, the mushroom is rather fragile. The spore deposit is yellow, and the flesh is white.

Relative to other typical mushroom species, the spores of ''V. bohemica'' are huge, typically measuring 60–80 by 15–18 µm. They are elliptical, smooth, sometimes curved, and appear hyaline to yellowish. The spores, which number two per ascus are characteristic for this species. The smooth, elliptical asci measure 275–350 µm long by 16–23 µm wide. The British-Canadian mycologist Arthur Henry Reginald Buller determined that the asci are heliotropic—they bend toward light. As he noted, "I cut transverse sections though their pilei, examined these sections under the microscope, and at once perceived that in all the hymenial grooves and depressions the asci were curved outwards so that their opercula must have faced the strongest rays of light to which the ends of the asci has been subjected in the places where the fruit-bodies developed." This response to the stimulus of light is significant because it permits a fruit body to point and later discharge its asci towards open spaces, thus increasing the chances that the spores will be dispersed by wind. The paraphyses are thick and club-shaped, with diameters of 7–8 µm at their tips.

Naming

The species was first described in the scientific literature by the Czech physician and mycologist Julius Vincenz von Krombholz in 1828, under the name ''Morchella bohemica''. The German naturalist Joseph Schröter transferred it to the genus ''Verpa'' in 1893. ''Ptychoverpa bohemica'' is a synonym that was published by Frenchman Jean Louis Émile Boudier in his 1907 treatise on the Discomycetes of Europe; the name is still occasionally used, especially in European publications. Boudier believed that the large, curved ascospores and the rare and short paraphyses were sufficiently distinct to warrant a new genus to contain the single species. ''Ptychoverpa'' has also been classified as a section of ''Verpa''. The section is characterized by the presence of thick longitudinal ridges on the cap that can be simple or forked.

The specific epithet ''bohemica'' refers to Bohemia , where Krombholz originally collected the species. The mushroom is commonly known as the "early morel", "early false morel", or the "wrinkled thimble-cap". ''Ptychoverpa'' is derived from the Ancient Greek ''ptyx'' , meaning "fold", layer", or "plate".The closely related species ''Verpa conica'' typically has a smooth cap, although specimens with wrinkled caps are known. ''V. conica'' may be distinguished microscopically by its eight-spored asci. Its North American range extends much further south than ''V. bohemica''. Another similar group of species are the "half-free" morels, ''Morchella semilibera'' and others, which have a honeycombed cap that is attached to the stalk for about half of its length, and with ridges that are darker than the pits. Additionally, a cross-sectioned stem of a specimen of ''M. semilibera'' is hollow, while ''V. bohemica'' usually has cottony wisps in the stem, and ''M. semilibera'' usually has vertical perforations near the base, while ''V. bohemica'' lacks them. ''Verpa bohemica'' may be reliably distinguished from all similar species by its much larger spores.

Distribution

The fruit bodies of ''V. bohemica'' grow singly or scattered on the ground in woods in early spring, often before the appearance of the morel, and throughout the morel season. It is often found along riverbanks, near cottonwoods, willows and aspens, often buried in plant litter. The fungus prefers to fruit in moist areas with ample sunlight. Its minimum growth temperature is 3 °C , with an optimum of 22 °C , and a maximum of about 30 °C . A study of carbon and nitrogen isotope ratios indicated that ''Verpa bohemica'' is saprobic, that is, obtaining nutrients from decomposing organic matter. It has been suggested, however, that the fungus is mycorrhizal for at least part of its life cycle. The fungus has a wide distribution throughout northern North America; its range extends south to the Great Lakes in the Midwestern United States, and south to northern California on the West Coast. In Europe, the fungus is widely distributed, and has been collected from Austria, the Czech Republic, Denmark, Finland, Germany, Norway, Poland, Russia, Slovenia, Spain, Sweden, and the Ukraine. In Asia, it has been recorded from India and Turkey.

A 10-year study of the distribution, time of fruiting and habitats of morel and false morel population in Iowa showed that early false morels are the first morels to fruit in the spring, appearing shortly after leaves begin to form on deciduous trees. Narrow-head morels fruit next, followed by the yellow or white morels , then lastly ''Morchella crassipes''. The fruit bodies serve as a habitat for breeding dipterans , including ''Porricondyla media'', ''Pegomya geniculata'', and ''Trichocera annulata''.

Habitat

The fruit bodies of ''V. bohemica'' grow singly or scattered on the ground in woods in early spring, often before the appearance of the morel, and throughout the morel season. It is often found along riverbanks, near cottonwoods, willows and aspens, often buried in plant litter. The fungus prefers to fruit in moist areas with ample sunlight. Its minimum growth temperature is 3 °C , with an optimum of 22 °C , and a maximum of about 30 °C . A study of carbon and nitrogen isotope ratios indicated that ''Verpa bohemica'' is saprobic, that is, obtaining nutrients from decomposing organic matter. It has been suggested, however, that the fungus is mycorrhizal for at least part of its life cycle. The fungus has a wide distribution throughout northern North America; its range extends south to the Great Lakes in the Midwestern United States, and south to northern California on the West Coast. In Europe, the fungus is widely distributed, and has been collected from Austria, the Czech Republic, Denmark, Finland, Germany, Norway, Poland, Russia, Slovenia, Spain, Sweden, and the Ukraine. In Asia, it has been recorded from India and Turkey.

A 10-year study of the distribution, time of fruiting and habitats of morel and false morel population in Iowa showed that early false morels are the first morels to fruit in the spring, appearing shortly after leaves begin to form on deciduous trees. Narrow-head morels fruit next, followed by the yellow or white morels , then lastly ''Morchella crassipes''. The fruit bodies serve as a habitat for breeding dipterans , including ''Porricondyla media'', ''Pegomya geniculata'', and ''Trichocera annulata''.