A medium-sized pure-white Myxacium, remarkable for its persistently white, strongly glutinous pileus and stipe, white to pale argillaceous to chocolate-brown lamellae, and mild taste. One of the few NZ Cortinarius species that remains entirely white when young, with no lilac, yellow, or brown pigments until the lamellae mature.

Cap: Up to 50 (-70) mm diam.; hemispherical with strongly inrolled margin, becoming umbonate‑convex, finally expanded with broad umbo. Colour persistently white, sometimes with a pale grey sheen from dried gluten. Surface strongly glutinous, even when dry; smooth or radially wrinkled. Margin non-striate.
Lamellae: (15-20, with 3-5-7 tiers of lamellulae). Attachment emarginate, often subdecurrent with a short tooth. Up to 5 mm wide. Colour whitish to pale argillaceous to coffee-brownto chocolate-brown with a ferruginous tinge. Edges white or grey, fimbriate, sometimes gelatinised.
Stipe: Up to 65 x 10 mm; fusoid to subclavate, rarely cylindrical or tapering. Colour white. Surface glutinous; young specimens may show fibrillose to submembranous cortina remnants. Base often with white rhizomorphs. Solid to hollow with age. Solitary or cespitose.
Context: White, sometimes pale yellow in stipe base.
Odour/taste: Odour indistinct. Taste mild.