Ravenel's Stinkhorn
Phallus ravenelii
Also called ravenel's phallus, wood chip stinkhorn
A North American stinkhorn with a nearly smooth, granular head rather than the honeycombed network of its relatives, rising from a pinkish-purple egg on sawdust and wood chips.
Overview
Phallus ravenelii is one of the most frequently encountered stinkhorns in eastern North America, especially around sawdust piles, wood chip beds, old stumps and cultivated ground with buried wood. It follows the standard stinkhorn pattern — a buried gelatinous egg that ruptures to release a rapidly elongating spongy stalk topped by a spore-bearing head — but differs from most Phallus species in the texture of that head.
Where the common stinkhorn and the dune stinkhorn bear a coarse honeycomb of ridges and pits, the head of P. ravenelii is essentially smooth beneath the slime, its surface finely granular or minutely wrinkled rather than deeply reticulate. Once insects strip the gleba away, the bare head appears pale and evenly textured with a conspicuous white ring or disc at the tip.
The species is named for the nineteenth-century American mycologist Henry William Ravenel. It often fruits gregariously, sometimes in impressive numbers where wood waste has been piled, and eggs may be found in quantity just beneath the surface before any have expanded.
How to identify it
Egg stage
A firm, ovoid egg 2–5 cm across, usually partly buried, with an outer skin that is whitish flushed pink, lilac or purplish, sometimes strongly so. White to pinkish rhizomorph cords run from the base. A vertical cut shows a thick gelatinous layer, the folded stalk and the dark gleba layer over the head.
Stalk
The stipe expands to 10–18 cm tall and 1.5–3 cm thick, white to very pale pinkish, hollow, cylindrical and spongy with a chambered, pitted wall. It stands in a loose, sac-like volva formed from the remains of the egg, which frequently keeps a pink or purplish flush.
Head
Thimble- to bell-shaped, 2–4 cm tall, attached to the stalk apex and free at the lower margin. Its surface is smooth to finely granular, mealy or minutely wrinkled, but without the deep honeycombed pits and raised ridges typical of P. impudicus and P. hadriani. The apex bears a distinct white perforate disc.
Gleba & spores
When fresh the head is coated in a dark olive to olive-brown sticky gleba, strong-smelling and fluid. Spores are contained in this slime rather than shed as a dry print; they are small, smooth and ellipsoid, and the deposit reads olive-brown.
Where and when it grows
Phallus ravenelii is a fungus of wood waste and rich, disturbed ground. Its typical substrates are sawdust and wood chip piles, mulched beds, rotting stumps and buried roots, decaying logs, old lumber yards and gardens with plenty of woody organic matter. It also fruits in lawns and cultivated soil where buried wood is present.
It is common through eastern and central North America, from the Great Lakes and southern Canada south to the Gulf states, with scattered records further west and reports from other regions. Fruiting occurs mainly in summer and autumn, particularly following warm, wet spells, and it can appear in large gregarious troops where a suitable pile of wood waste has been colonised.
Ecological role
This stinkhorn is a saprotroph specialising in woody debris. Its mycelium colonises sawdust, chips, stumps and buried timber, breaking down cellulose and lignin and binding the substrate with visible white cords that lead to each developing egg. Because piled wood waste holds moisture and warmth, colonies there can be extremely productive.
Spore dispersal depends entirely on insects. The gleba releases a strong, carrion-like odour as it liquefies, attracting flies, beetles and other visitors that feed on the slime. Spores stick to their legs and bodies and pass unharmed through their digestive tracts, so the fungus is spread to new sites in a way that wind dispersal could not achieve. Heads are often picked clean within a day, leaving the pale smooth head and white stalk standing until the tissue collapses.
Similar species
Phallus impudicus is separated by its coarsely pitted, honeycomb-ridged head and its white, non-purplish egg and volva. Phallus hadriani also has a strongly reticulate head and, although its egg is violet-tinted like that of P. ravenelii, it is a sand-dune and sandy-soil species rather than a wood-waste one.
Phallus duplicatus and Phallus indusiatus both hang a net-like skirt (indusium) from beneath the head, which P. ravenelii never produces. Mutinus species are far more slender, orange to pink, and lack a distinct free-margined head, the gleba simply coating the tapering upper stalk. Unopened eggs resemble small puffballs from outside, but slicing one lengthwise reveals the gelatinous layers and the dark gleba band of a stinkhorn.