Stinky Squid
Pseudocolus fusiformis
Also called squid stinkhorn, three-armed stinkhorn
A small stinkhorn with three or four tapering orange arms that rise from a short pale stalk and meet at the top, dark olive spore slime coating their inner faces.
Overview
The Stinky Squid is a compact stinkhorn whose common name captures its shape well: a short, pale, hollow stalk splits into a small number of tapering arms that arch upward and meet at a point, like a squid standing on its head.
Pseudocolus is a small genus in the family Phallaceae, and this species is also recorded under the names Pseudocolus schellenbergiae and Colus fusiformis. It differs from the free-armed Clathrus archeri in keeping its arms joined at the apex, and from the stalkless Clathrus columnatus in raising those arms on a distinct short column.
It is best known in eastern North America, where it fruits in landscaping mulch during warm humid weather, and also occurs in parts of Asia, Australasia and elsewhere.
How to identify it
Stalk
A short, whitish to pale pinkish stalk about 1–3 cm tall and 1–2 cm thick, hollow and spongy-chambered, emerging from a whitish, membranous volva that often remains partly buried in the substrate.
Arms
Usually three arms, sometimes four, each 2–5 cm long, tapering evenly toward the tip and fused together at the apex so the fruiting body forms a narrow closed cage. Arms are orange to orange-red, sometimes yellowish or pinkish, wrinkled and finely chambered on the outer surface, and often slightly grooved along their inner faces.
Gleba and flesh
Dark olive-brown to blackish spore slime coats the inner surfaces of the arms, mostly toward the upper half. Total height is generally 3–8 cm, making this one of the smaller cage-type stinkhorns. The tissue is soft and water-filled, collapsing rapidly. The egg is whitish, 1.5–3 cm across, with a gelatinous inner layer over the pre-formed arms.
Where and when it grows
It fruits on wood chips, bark mulch, sawdust, compost, rich garden soil and deep hardwood leaf litter, and is most often reported from landscaped beds, path edges and plant nurseries. Fruitings can be dense, with dozens of eggs opening in a single mulched border after a soaking rain.
The main season is summer to early autumn in temperate regions, extending longer in warm climates. It is widespread in eastern North America, with records also from the Pacific Northwest, eastern Asia, Australia, New Zealand and scattered points elsewhere, its spread aided by the movement of mulch.
Ecological role
Pseudocolus fusiformis is saprobic on woody debris, breaking down bark and wood fragments in the mulch layer. Whitish rhizomorphs run through the substrate and swell into eggs at the surface, which explains the clustered, near-simultaneous fruitings often seen in gardens.
Spore dispersal depends on insects drawn to the strong odour of the gleba. Flies and beetles crawl inside the small cage or over its arms, feed on the slime and depart carrying spores. The narrow closed arms concentrate scent and slime in a small volume close to the ground.
Similar species
Clathrus columnatus is larger, has its columns rising separately straight from the volva with no intervening stalk, and its columns are stouter and less evenly tapered. Clathrus archeri opens into four to eight free arms that flatten outward instead of remaining joined at the tip.
Lysurus mokusin has a much longer, sharply fluted stalk and only short arms at the top. Aseroe rubra has an expanded flat disc with forked rays and central gleba. Among small orange fungi in mulch, the combination of a short pale stalk, three tapering fused arms and a white volva is diagnostic here.