D&D Mycology Handbook: Fungus Caverns I

Fungus caverns are a classic archetype of weird fiction, and have accordingly been incorporated into fantasy roleplaying environments since the birth of the hobby. Although many DMs treat fungus caverns simply as colorful backdrops for spelunking, it is not unknown for some players to want to take a closer look at the mycological wonders surrounding them. To better serve these supernaturalistic gameplay moments, I here begin a series of reports providing some rudimentary details on the ecology and diversity of common subterranean fungi in the world of Oranj.

Consider the mushroom… It is only the transitory fruiting body, the fleeting flesh flower if you will, of a more cryptic and expansive organism that resides in the soil. The main part of the organism is in fact the mycelium – a neural net of fibrous aspect that may extend for inches or miles. Some fungi of Oranj have mycelia that extend not only through the earth, but also across several obscure dimensions of space.

The defining feature of a fungus cavern is the nutrient source of the resident fungi. The fungi of the surface world typically live on decaying organic matter. A paucity of sunlight in subterranean regions translates into a lack of plant matter, which in turn means that there is very little decaying organic stuff to sustain forests of mundane fungi deep underground. The great fungi of the inner sphere instead rely on more unusual strategies for survival:

1. Mycocultural Tracts: Underground mushroom farms are actively maintained by fungus feeding lifeforms. To support this type of agriculture organic material is actively brought into the caverns and applied to the mushroom gardens. The constitutive fungi are usually benign, sometimes delicious. Mushroom farms are usually indicative of a local subterranean agricultural society.

2. Filth Springs of the Inner Sphere: On Oranj there are poorly understood underground reservoirs of organic filth that occasionally bubble through into caverns. These springs of filth often form ponds or lakes of thick oily sludge that can support large patches or even floating islands of fungus. Some of these fungus islands are quite large and ancient, manifesting as massive floating mushroom forests in the deepest caverns.

3. Calxomyces Galleries - Stone Eaters: Certain Oranjian fungi are capable of feeding upon rocks and minerals. Most common of these "stone eater" fungi are the carbonophilic calxomyces. The mycelia of these fungi spread through caverns, actively breaking rock in order to gain access to veins of coal or similar carbon-rich sediments. This bizarre feeding strategy has lead to the creation of vast cavern systems throughout the planet's crust. The multichromatic mycelia of calxomyces can completely cover the interiors of active feeding caverns, producing an otherwordly environment where sensitive travelers can telepathically sense the thoughts of the mycelia. Calxomyces fruiting bodies are large black and purple morel-like growths.

NEXT POST:

Flesh Eating Fungus Nests

Mycelial Brain Cysts

Interdimensional Sporulation Patches

Undead Fungus

The Fungus Caverns of Etidorhpa (Lloyd 1895)

It's probably safe to say that we all love the idea of subterranean caverns filled with strange oversized fungi. I certainly do. Because fungi survive by decomposing decaying organic matter, however, it actually makes very little biological sense for a deep cavern system to support forests of gigantic mushrooms, unless, of course, some ultramundane forces are at play. For me, this hint of magic actually makes the vision all the more appealing. Eventually, I hope to compose several substantial posts on the supernatural history of fungus caverns. For now though, I would like to point out an early and lesser known bit of fantastic fiction describing a fungus forest: Etidorhpa by John Uri Lloyd, published in 1895.

Lloyd was a pharmaceutical chemist who had never published fiction before the release of Etidorhpa (which is Aphrodite spelled backwards, by the way). This book is a weirdly charming yarn and an early landmark in the hollow earth genre. Lloyd was heavily involved in freemasonary, which is a prominent theme in the book. Etidorhpa has excited the sensibilities of some folks in much the same way that the Amazing Stories Shaver Mystery did 50 years later - both having lead especially sensitive readers to believe that some elements of mystical truth might underlie the fiction.

From a mycological perspective, the more entertaining parts of Etidorhpa are this illustration and text describing a great fungus cavern (yes, that is a nude hairless humanoid with no eyes):

"Along the chamber through which we now passed I saw by the mellow light great pillars, capped with umbrella-like covers, some of them reminding me of the common toadstool of upper Earth, on a magnificent scale. Instead, however, of the grey and somber shades to which I had been accustomed, these objects were of various hues and combined the brilliancy of the primary prismatic colors, with the purity of clean snow. Now they would stand solitary, like sentinels; again they would be arranged in rows, the alignment as true as if established by the hair of a transit, forming columnar avenues, and in other situations they were wedged together so as to produce masses, acres in extent, in which the stems became hexagonal by compression. The columnar stems, larger than my body, were often spiral; again they were marked by diamond-shaped figures, or other geometrical forms in relief, beautifully exact, drawn as by a master’s hand in rich and delicately blended colors, on pillars of pure alabaster. Not a few of the stems showed deep crimson, blue or green, together with other rich colors combined; over which, as delicate as the rarest of lace, would be thrown, in white, an enamel-like intricate tracery, far surpassing in beauty of execution the most exquisite needle-work I had ever seen. There could be no doubt I was in a forest of collossal fungi, the species of which are more numerous than those of upper earth, cryptomatic vegetation."

In the book it turns out that these titanic mushroom forests are a perfect food source for the humans who eventually forsake the surface of the earth to exult in a new immaculate existence in the inner sphere. If so inclined, you may read the full text of Etidorhpa here. Enjoy.