Red Cage

The Red Cage is the best-known member of Clathrus, a genus of stinkhorns whose receptacle is not a column but a closed, hollow network. There is no stalk and no cap: the entire fruiting body is a latticed sphere or egg-shaped ball built from fused, spongy arms.

It develops inside a partly buried egg, typically 2–6 cm across, whitish to greyish and attached to the ground by a stout white rhizomorph. Slicing an egg lengthwise shows the folded lattice already complete, compressed inside a thick gelatinous layer. Expansion is dramatic and fast, and the delicate cage may collapse into an orange heap by the following day.

It is native to the Mediterranean region and warm parts of Europe, and has spread widely with landscaping materials, so it now turns up unexpectedly in gardens far outside its original range.

Fruiting body

A hollow, roughly spherical to broadly ovoid lattice 5–15 cm across at maturity, sitting directly on or just above the ruptured egg. The lattice is composed of thick, flattened, spongy arms that fuse at their junctions to enclose irregular polygonal windows, larger toward the middle of the sphere and smaller near the base.

Arms

Arms are coral-red to orange-red, occasionally fading to orange or pinkish with age or in shade. Their outer surface is wrinkled, pitted and finely chambered; in cross section they are spongy and hollow, and they crush easily between the fingers.

Gleba and base

The dark olive-brown to blackish spore slime coats the inner surfaces of the arms, so a fresh specimen looks bright red from the outside and dark from within. Below, the lattice arises from a persistent whitish to pale pinkish volva with a thick gelatinous inner layer and a white basal cord. There is no spore print in the usual sense — spores are carried off in the slime rather than dropped from a fertile surface.

Clathrus ruber is a decomposer of woody and leafy organic matter. It is most often found in wood chip mulch, compost-enriched garden beds, hedge bases, roadside plantings and disturbed ground at woodland edges, usually in soil with plenty of buried plant debris. It also fruits in leaf litter under Mediterranean shrubland and mixed hardwoods.

Fruiting follows rain during mild to warm weather and can occur from spring through late autumn, with the strongest flushes in humid warm periods. Its natural range centres on southern Europe and North Africa, but transported mulch and nursery stock have carried it to Britain, central Europe, North America, Australia and elsewhere.

The species is saprobic, feeding on decaying wood fragments, bark and litter through a network of white rhizomorphs that terminate in eggs at the soil surface. Because it thrives on fresh organic mulch, populations often flare up a year or two after new landscaping and then fade as the substrate is exhausted.

Reproduction relies on insects. The gleba produces a powerful fetid odour that draws blowflies and beetles into the cage, where they feed on the slime lining the inner arm surfaces; spores pass through or stick to the visitors and are dispersed. The bright red lattice may add a visual cue to the chemical one.

Clathrus archeri (Devil's Fingers) begins as a similar egg but opens into separate, free arms that splay outward like a starfish, never forming a closed sphere. Clathrus columnatus has just two to five thick vertical columns that are free at the base and joined only at the apex, leaving a wide arch rather than an all-over mesh.

Ileodictyon cibarium forms a comparable lattice ball but is white to cream rather than red, with arms rounded in cross section, and the whole receptacle detaches from its volva at maturity. Young unopened eggs of Clathrus ruber can be confused with the eggs of Phallus species and with small puffballs; a vertical cut settles it — puffballs are uniformly firm and white inside, while stinkhorn eggs show a gelatinous layer surrounding a compressed, pre-formed receptacle.