Dune Stinkhorn

Description

The dune stinkhorn starts out as a spherical or egg-shaped "egg" 4–6 cm in size, pinkish to violet, partly sunk in the sand. From the egg a white, spongy stem, hollow inside, quickly grows, usually 6–10 cm tall (up to 20 cm), topped with a thimble-shaped, ridged head covered in an olive, slimy ooze. A cup-like volva, most often pink or violet-tinged, remains at the base.

It grows in summer and autumn on dry, sandy coastal dunes of the Baltic, sporadically also inland. In Poland it is very rare. The fruiting body is short-lived, usually lasting one to two days, and the ooze attracts insects, which spread the spores. The smell can be weaker than in the common stinkhorn, and descriptions range from slightly pleasant to foul.

It is most easily confused with the common stinkhorn. The dune stinkhorn has a pink or violet volva, a smaller disc at the top of the head and a weaker smell, and it grows on dunes. It is an inedible mushroom.

Identification features

Cap

The true cap is thimble-shaped; the surface is reticulately ridged and pitted, covered with an olive-green, slimy spore-bearing mass (gleba). Soon after the fruiting body expands, the gleba liquefies and gives off an odour that attracts insects. At the top there is a small disc (smaller than in Phallus impudicus).

Hymenophore (underside of the cap)

No gills or tubes: the spore-bearing layer (gleba) covers the reticulate, ridged head and takes the form of an olive slime.

Stem

Height up to 20 cm, usually 6–10 cm (young fruiting bodies reach 10–20 cm), thickness 3–4 cm. Colour white or cream; the stipe is hollow inside, spongy, with numerous chambers, and very brittle. At the base there is a cup-like volva, usually pink or violet-tinged, which may turn brown with age. Young fruiting bodies take the form of an egg measuring 4–6 × 3–4 cm, pinkish-lilac to violet, embedded in the soil and attached by rhizomorphs; the egg is enclosed by a tough covering with a gelatinous layer, which breaks down during growth. The fruiting body usually lives for one to two days.

Flesh

The flesh of the stem is whitish, spongy, chambered and very brittle. The smell is weaker than in the common stinkhorn; it is described variously, from faint, pleasant and reminiscent of violets, to foul and putrid. The flesh should not be tasted.

Spore print and spores

Spores cylindrical, smooth, hyaline (colourless), 3–4 × 1–2 µm. The spores are found in the olive gleba, which is dispersed mainly by insects.

Habitat and distribution

Ecology. Saprotroph, decomposing dead organic matter. In North America often associated with stumps or the roots of decaying stumps; in Great Britain mostly on coastal dunes; in Poland it avoids moist, humus-rich forest soils and grows on dry sands, accompanied by xerophilic grasses and black locust (Robinia pseudoacacia). It attracts flies, bees and beetles, which eat the gleba and spread the spores; the spores can survive passage through the insects' digestive tract.

Distribution. Very rare in Poland, on sandy, dry coastal dunes of the Baltic, sporadically inland. Widespread in Eurasia and North America (including Denmark, Ireland, Latvia, the Netherlands, Norway, Slovakia, Sweden, Ukraine, Wales, Turkey, Japan and China); in Australia probably an introduced species, brought in with wood chips. On the Red List of Plants and Fungi of Poland it is in category V (vulnerable). Until 9 October 2014 it was under strict protection in Poland; it is now not legally protected (Dz.U. 2014 item 1408). It is protected by the Latvian Red Data Book.

Fruiting. Summer and autumn.

What can it be confused with?

• Phallus impudicus (common stinkhorn) — Volva white (pink or violet in the dune stinkhorn), larger disc at the top of the head, stronger, distinctly foul smell; grows in other habitats, not on dunes.
• Phallus ravenelii — Head smooth, not reticulate.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The species name commemorates Hadrianus Junius, a Dutch humanist and botanist who in 1564 described stinkhorns growing on the Dutch dunes.
• On 30 June 1980 Poczta Polska (the Polish Post) issued a 2.5 zł stamp featuring the dune stinkhorn in the series "Protected Inedible Mushrooms"; 9,695,000 copies were printed.
• The fruiting body usually lives for one to two days, and after expansion the gleba quickly liquefies and attracts flies, bees and beetles.
• In Poland it was a strictly protected species, and since 9 October 2014 it has not been legally protected.