Bull-nose False Morel
Gyromitra korfii
Also called bull nose, korf's false morel, bull-nose gyromitra
A stout spring ascomycete with a bulging tan-brown head thrown into broad rounded lobes and folds, perched on a thick chambered white stalk. Its smoothly convoluted surface, without any true pits and ridges, sets it apart from the true morels.
Overview
The Bull-nose False Morel is one of the large, fleshy spring ascomycetes of the genus Gyromitra, in the family Discinaceae. Its bulky, blunt-lobed head gives it the nose-like profile behind the common name, and among the false morels it is one of the paler and more rounded species.
Gyromitra species differ from the true morels of Morchella by carrying their spore-bearing layer over a smooth to wrinkled or brain-like surface rather than inside a honeycomb of pits. In this species the head is inflated and irregularly folded into a few broad lobes, with the surface undulating gently rather than being sharply ribbed.
The stalk is the second half of the identification. It is thick, pale, and internally divided by folded walls into chambers and channels, so a lengthwise cut reveals a complicated interior rather than a single clean hollow. That combination of a tan bulging head and a chambered white stalk is diagnostic in the field.
How to identify it
Head
The fertile head is 4-12 cm wide, bulging and irregularly rounded, thrown into a few broad shallow lobes and low undulating folds. It is tan, cinnamon, ochre-brown or warm reddish-brown, dry and slightly matt, and the underside of the lobes is paler and rolls under, attaching to the stalk at several points rather than hanging entirely free.
Surface texture
Unlike a true morel there are no pits and no raised network of ridges. The wrinkles are broad and rounded, closer to the creases of a brain or a folded cloth, and they never form a regular honeycomb pattern.
Stipe
Stout and thick, 3-10 cm tall and often 2-5 cm wide, white to cream, sometimes flushing pale buff with age. The surface may be smooth or shallowly grooved. Cut lengthwise, the interior is not a simple hollow tube but is divided by infolded walls into several irregular chambers and pockets.
Flesh and spore print
The flesh is white, brittle and fairly thick, without notable colour change when cut. The spore deposit is white to pale cream, and the spores are large, ellipsoid and finished with a small apiculus or blunt projection at each end.
Where and when it grows
The Bull-nose False Morel fruits on the ground in rich humus and leaf litter, most often in deciduous or mixed forest. It shows a preference for hardwood stands with ash, elm, maple, oak and tulip poplar, and appears along old logging roads, on wooded slopes and in floodplain woodland where the soil stays damp.
It is a spring species, emerging as soil temperatures rise and frequently overlapping with the early morel season. It is mainly reported from eastern and central North America, with related and easily confused species occurring elsewhere in temperate forests of the northern hemisphere.
Ecological role
Like other members of the Discinaceae, this fungus is generally regarded as saprotrophic, drawing nutrients from decaying leaf litter, buried woody debris and humus-rich soil rather than forming a root partnership. The mycelium runs through the litter layer and upper soil, and fruit bodies push up from buried wood fragments and accumulated organic matter.
Fruiting is triggered by the combination of spring warming and consistent soil moisture, and it is often brief, with a flush lasting only a week or two at a given site. Ascospores are discharged from the exposed convoluted surface of the head and carried away on air currents; released spores may lie dormant in the soil until conditions favour new colonisation.
Similar species
True morels, Morchella species, are the most frequent confusion. A morel has a head hollowed into a regular honeycomb of sunken pits framed by raised ridges, and cutting one lengthwise reveals a single continuous hollow running from the tip of the cap into the base of the stalk. The Bull-nose has rounded folds instead of pits and a stalk broken up by internal chambers.
Gyromitra brunnea is darker and its head is more sharply saddle-shaped, with two or three pointed lobes that hang free of the stalk. Gyromitra caroliniana is larger and more strongly reddish-brown, with deep, tightly packed convolutions across the whole head. Gyromitra esculenta is much more finely and densely wrinkled, distinctly reddish-brown, and grows chiefly with conifers on sandy soil. Verpa bohemica differs again: its wrinkled thimble-like cap hangs free from the top of a slender stalk that is stuffed with cottony pith.