Vinegar cup or White saddle

Fruit body up to 8 cm across, cup- or saucer-shaped, 2-4 cm deep. Outer surface yellowish brown, finely warty; inner surface (where the hymenium lies) smooth, yellowish gray-brown, with a silky sheen. Margins thin, often split in mature cups, with an uneven outline.

Cap 2-4 cm, irregularly saddle-shaped, with 2-4 lobes that look like crumpled fabric. Color white or creamy white, with a yellowish tinge in wet weather. Surface smooth on the outside (where the hymenium is), finely warty underneath. Partly fused to the stem at the top. Margins contorted, uneven.

Smooth hymenium on the inner surface of the cup. Spores mature in asci within the hymenial layer. Spore print whitish to cream, spores elliptical, smooth. Chemically, a typical ascomycete.

Smooth hymenium on the upper (outer) surface of the cap lobes. Ascomycete structure — spores form in asci. Spore print white. Spores ellipsoid, smooth, with one large oil droplet.

Stem short, 2-4 cm tall, 1-2 cm thick, with sharply defined lengthwise ribs that run up to the base of the cup and continue onto its outer surface. Color cream or whitish. This is the key diagnostic feature of the species.

Stem up to 10 cm tall, 1-2.5 cm thick, cylindrical, hollow inside. Color white, smooth to the touch, BUT with prominent lengthwise ribs (grooves) running its whole length. This is the key feature — a ribbed white stem.

The flesh is thin, waxy and brittle, whitish. Doesn't change color when cut. Fragile texture, like in all Helvella.

The flesh is thin, waxy and brittle, white. Doesn't change color when cut. Fragile texture — the mushroom easily falls apart if handled carelessly.

No pronounced smell, faintly mushroomy. We don't taste it — the mushroom is potentially toxic when raw.

Faint, nondescript mushroomy smell. Don't taste it raw — potentially toxic.