Hypomyces cervinigenus

🏷️ Description

If you ever spot a once proud Helvella mushroom (the famous Elfin Saddles) mysteriously coated in a white to pinkish fuzz, you might have just met Hypomyces cervinigenus — a fascinating parasitic fungus lurking across Europe, North America, and beyond! 🌎🍂

🧬 Taxonomy and Discovery: First described in 1971 by Clark Rogerson and Horace Simms, Hypomyces cervinigenus made its scientific debut in Pierce County, Washington. It was initially found on what was thought to be Helvella lacunosa — although later DNA studies revealed North America’s "H. lacunosa" is actually H. dryophila and H. vespertina. 🔍

Taxonomically, this species seems to sit between classic Hypomyces like H. lactifluorum and relatives such as H. polyporinus based on spore features. Its anamorph (asexual stage) is called Mycogone cervina.

🍥 Appearance and Growth

Hypomyces cervinigenus begins life with a soft, cottony white subiculum (a mat of fungal threads) that slowly tightens into a compact layer. As it matures:

• The surface turns pinkish ➡️ cream-buff ➡️ powdery light brown over time.

• It grows over the cap and stipe (stem) of its unlucky Helvella host.

• In warm climates, it can even fruit through winter! ❄️🌸

The perithecia (fruiting structures) are:

• White to pale buff initially

• Waxy and translucent when fresh

• Later amber or light yellow as they age and dry

• Shaped like tiny spheres or eggs (165–385 μm high × 130–265 μm wide)

🔬 Microscopic Details

Zooming in reveals a microscopic world teeming with intricate structures:

Ascospores:

• Smooth, hyaline (transparent), spindle-shaped (fusiform)

• 15–26 × 2–5 μm, usually 2-celled with a slightly pointed upper end and a blunt lower end

• Arranged neatly in a row inside the asci

Asci:

• Slender and long, 100–142 × 2–4.5 μm

• With a thickened cap and a pore for spore release

Asexual spores (very common!):

• Aleuriospores: Round, spiny, thick-walled, 13.5–17.5 μm, pinkish-buff in mass

• Conidia: Cylindrical-ellipsoid, 14–25.5 × 4–5 μm, smooth, sometimes septate

KOH on the surface: Negative. 🎯

🌍 Distribution and Habitat

Where can you find this sneaky fungus?

• Widespread across North America (from California to Illinois to Alaska) 🌎

• Occasionally reported from Europe (Germany, Norway, Estonia, Netherlands), and even Japan and Kazakhstan!

• Most commonly seen parasitizing Helvella vespertina and Helvella dryophila.

It thrives from summer to fall or over winter in milder climates, especially in forests rich with Helvella mushrooms.

🍽️ Edibility

Hypomyces cervinigenus is not edible — but it’s unlikely you’d want to eat a mummified, fuzzy Elfin Saddle anyway! 🤢🍄

📜 Synonyms

• Mycogone cervina Ditmar (1817)

• Racodium mycobanche Persoon (1822)

• Sepedonium cervinum (Ditmar) Fries (1832)

• Mycobanche cervina (Ditmar) Wallroth (1833)

• Puccinia cervina (Ditmar) Corda (1839)

• Sepedonium fuscum Bonorden (1851)

• Mycogone simplex Corda (1854)

• Hypomyces cervinus Tulasne & C. Tulasne (1860)

• Sepedonium cervinum var. subincanatum Peck (1880) [1879]

• Sepedonium cordae Saccardo (1886)

• Hypolyssus cervinus (Tulasne & C. Tulasne) Kuntze (1898)

• Sepedonium simplex (Corda) Lindau (1905)

• Mycogone cervina var. subincarnata (Peck) Peck (1911) [1910]

• Sepedonium subincarnatum (Peck) Saccardo (1931)

💬 Final Thoughts

This remarkable parasite transforms gray-black Elfin Saddles into ghostly white, pinkish, or cocoa-brown shells, thanks to a vigorous covering of asexual spores. Interestingly, the sexual structures (perithecia and ascospores) are rarely seen in nature — so much so that it was long known only by its asexual name, Mycogone cervina.

As DNA research digs deeper, new species closely related to H. cervinigenus may yet emerge, especially from the hidden world of Helvella parasites.

Photo sources:

Photo 1 - Author: Don Loarie (CC BY 4.0)

Photo 2 - Author: Karen Offereins (CC BY 4.0)

Photo 3 - Author: Reagan peschke (CC BY 4.0)

Photo 4 - Author: Chloe and Trevor Van Loon (CC BY 4.0)