Early morel

Description:

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.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.[15] 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.[13] The spores, which number two (more rarely three)[16] per ascus are characteristic for this species.[10] The smooth, elliptical asci measure 275–350 µm long by 16–23 µm wide.[17] 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."[18] 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.[18] The paraphyses are thick and club-shaped, with diameters of 7–8 µm at their tips.

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.[5] It is often found along riverbanks, near cottonwoods, willows and aspens, often buried in plant litter.[11] The fungus prefers to fruit in moist areas with ample sunlight.[28] Its minimum growth temperature is 3 °C (37 °F), with an optimum of 22 °C (72 °F), and a maximum of about 30 °C (86 °F).[29] A study of carbon and nitrogen isotope ratios indicated that Verpa bohemica is saprobic, that is, obtaining nutrients from decomposing organic matter.[30] It has been suggested, however, that the fungus is mycorrhizal for at least part of its life cycle.[31] The fungus has a wide distribution throughout northern North America;[5] its range extends south to the Great Lakes in the Midwestern United States, and south to northern California on the West Coast.[17] In Europe, the fungus is widely distributed, and has been collected from Austria,[32] the Czech Republic,[33] Denmark,[32] Finland,[34] Germany,[35] Norway,[36] Poland,[37] Russia,[38] Slovenia,[32] Spain,[32] Sweden,[39] and the Ukraine.[40] In Asia, it has been recorded from India[41] and Turkey.[42]