Xerocrassa roblesi

Eremiaphila heluanensis

Verpa bohemica is a species of fungus in the family Morchellaceae. Commonly known as the early morel (or early false morel) or the wrinkled thimble-cap, it is one of several species known informally as a "false morel". The mushroom has a pale yellow or brown thimble-shaped cap—2 to 4 cm (0.8 to 1.6 in) in diameter by 2 to 5 cm (0.8 to 2.0 in) long—that has a surface wrinkled and ribbed with brain-like convolutions. The cap hangs from the top of a lighter-colored, brittle stem that measures up to 12 cm (4.7 in) long by 1 to 2.5 cm (0.4 to 1.0 in) thick. Microscopically, the mushroom is distinguished by its large spores, typically 60–80 by 15–18 µm, and the presence of only two spores per ascus.

In the field, the mushroom is reliably distinguished from the true morels on the basis of cap attachment: V. bohemica has a cap that hangs completely free from the stem. Although widely considered edible, consumption of the mushroom is generally not advised due to reports of poisoningin susceptible individuals. Poisoning symptoms include gastrointestinal upset and lack of muscular coordination. V. bohemica is found in northern North America, Europe, and Asia. It fruits in early spring, growing on the ground in woods following the snowmelt, before the appearance of "true morels" (genus Morchella). The synonym Ptychoverpa bohemica is often used by European mycologists.

Taxonomy, phylogeny, and 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 asynonym 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.^[5] 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.^[7] 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 (now a part of the Czech Republic), where Krombholz originally collected the species.^[2] 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 (genitive form ptychos), meaning "fold", layer", or "plate".

[edit]Description

Stems of young fruit bodies are initially stuffed with soft, cottony tissue.

The spores are large, measuring up to 80 µm long.

The cap of this fungus (known technically as an apothecium) is 2 to 4 cm (0.8 to 1.6 in) in diameter by 2 to 5 cm (0.8 to 2.0 in) long, with a conical or bell shape. It is folded into longitudinal ridges that often fuse together (anastomose) 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 (2.4 to 4.7 in) long by 1 to 2.5 cm (0.4 to 1.0 in) thick, cream-white in color, and tapers upward so that the stem is thicker at the base than at the top.^[13] Although the stem is initially loosely stuffed with cottony hyphae, it eventually becomes hollow in maturity; overall, the mushroom is rather fragile.^[14] 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 (translucent) to yellowish. The spores, which number two (more rarely three) 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.

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