Hooded False Morel

Gyromitra infula stands apart from most of its genus in two ways: its shape and its season. Instead of the tight brain-like convolutions typical of Gyromitra, its cap is folded into a broad saddle or mitre with two or three lobes whose surfaces are comparatively smooth. And instead of fruiting in spring, it appears from late summer through autumn, sometimes persisting into the first frosts.

The epithet infula refers to a bishop's mitre, and the resemblance is apt: two upright lobes lean together over a central ridge, giving the fungus a hooded, peaked profile that is unlike anything else fruiting at that time of year. The English name "elfin saddle" is shared with related fungi in Helvella, which have a comparable saddle geometry.

The species is widely distributed across the boreal and temperate northern hemisphere, in North America, Europe and Asia, and is a familiar sight on decaying conifer wood in autumn forests.

Cap

The cap is 3-12 cm across and folded into two, or sometimes three, lobes that rise and lean together, forming a saddle, mitre or hood with one or more longitudinal ridges. The surface is smooth to shallowly wavy or slightly wrinkled but is not densely convoluted or brain-like. Colour ranges from yellow-brown and tan through warm chestnut to dark reddish-brown or purplish-brown, often darkest at the ridges. The lobe margins are usually free and inrolled, and may touch or partly fuse to the stalk at a few points. The underside is pale, whitish to buff, and finely downy or smooth.

Stipe

The stalk is 3-10 cm tall and 1-3 cm thick, cylindrical or somewhat flattened and irregular, and often widening slightly downward. It is whitish, cream, pale pinkish-buff or tinged the colour of the cap, with a smooth to finely downy surface that may be shallowly grooved but is not deeply ribbed or fluted. Internally it is hollow or contains a few loose chambers.

Flesh & spore deposit

The flesh is thin, whitish and brittle, and does not change colour markedly when cut. A spore deposit is white to pale yellowish; the elliptical spores lack the pronounced apical points seen in some relatives.

The hooded false morel is a wood decomposer. It fruits on well-rotted conifer logs and stumps, on buried wood, on wood chips and sawdust, on mossy woody debris and on humus rich in decaying timber. It also appears on old burn sites and along disturbed forest tracks. Spruce, fir, pine and hemlock stands are typical settings, though it can occur in mixed forest and occasionally on hardwood debris.

Unlike almost all its spring-fruiting relatives, this species fruits from late summer through autumn, often peaking after the first cool wet spells and continuing until hard frost. Fruiting bodies may be solitary or in small clustered groups directly on rotten wood, where their dark saddles blend with the surrounding litter. It is widespread through boreal and montane forests of North America, Europe and northern Asia.

Gyromitra infula is a saprotroph specialising in the later stages of conifer wood decay. By the time it fruits, its substrate is usually soft, crumbly, moisture-holding and well colonised by other fungi, and the mycelium works through the residual cellulose and humified material of that advanced decay stage.

Spores are produced in asci covering the upper surface of the saddle-shaped cap and are shot into the air; the cap's raised, exposed geometry helps expose that fertile surface to air movement above the litter. Autumn fruiting positions the fungus in a very different competitive setting from its spring relatives, using the cool, damp conditions after summer drought when wood moisture is high. Its appearance on burn sites, wood chips and disturbed ground indicates a tolerance for altered, nutrient-shifted substrates, and within decaying logs it contributes to the final conversion of woody tissue into forest soil.

Gyromitra ambigua is nearly identical in shape and habitat, differing mainly in more pronounced violet or purplish tones and, decisively, in its longer spores; the two are often separated only under a microscope. Gyromitra esculenta is a spring species with a much more finely convoluted, brain-like cap and a shorter, stouter stalk.

Helvella species such as Helvella lacunosa share the saddle-shaped cap but are grey to black rather than warm brown, and have distinctly ribbed, fluted and chambered stalks rather than the smooth or shallowly grooved stalk of G. infula. Gyromitra brunnea has broader, more flaring lobes with pale margins, a stout ribbed stalk, and fruits in spring in hardwood forest rather than in autumn on conifer wood.