Xylaria hypoxylon
Description
Xylaria hypoxylon is an inedible species of fungus in the genus Xylaria. The fruit bodies, characterized by erect, elongated black branches with whitened tips, typically grow in clusters on decaying hardwood. The fungus can cause root rot in hawthorn and gooseberry plants.
This mushroom can be found year-round. The most commonly encountered form, with powdery whitish branch tips, is the asexual stage of the fungus. The sexual stage is less conspicuous as it lacks the white color; it is usually less branched (if at all) and has a rough warty surface from numerous small flask-like structures that produce the kidney-bean-shaped spores.
Xylaria hypoxylon is extremely variable in appearance, featuring a fruiting body that can be narrowly cylindric and pointed, or cylindric below but branched and flattened above, somewhat reminiscent of tiny moose antlers.
When found in the spring, the entire ascocarp may be white to grayish and powdery as a result of the formation of asexual spores. Later in the season, mature forms are blackish and minutely pimply. The small bumps are the locations of sexual spore-producing structures called perithecia.
Common names: Candlestick Fungus, Candlesnuff Fungus, Carbon Antlers, Stag's Horn Fungu, Geweihförmige Holzkeule (German), Xylaire du bois (French).
Mushroom Identification
Ecology
Saprobic on the deadwood of hardwoods; growing gregariously to densely gregariously; spring through fall; by strict definitions distributed in Europe and the West Coast of the United States, but (mis)reported as widely distributed in North America from Canada through Mexico—and in Central America, the Caribbean, South America, Africa, Asia, and Oceania.
Anamorphic Fruiting Body
2–10 cm long; 2–15 mm thick; either narrowly cylindric, with a pointy apex—or cylindric below but branched and flattened above, appearing somewhat like moose antlers, with tapering points on most branches; surface black and slightly fuzzy below, but powdery and gray to nearly white above; extreme apex attenuated, whitish to yellowish, and bald; sometimes with a rooting, black, stem-like structure; interior flesh white and tough.
Teleomorphic Fruiting Body
Shaped like the anamorphic fruiting body; surface black, bald, and finely pimply.
Microscopic Features
Conidia 5–11 x 2–3 µm; fusiform; smooth; hyaline in water and in KOH. Spores 13–16 x 5–6 µm; subfusoid to subellipsoid; smooth; brown to dark brown in water, with a single, straight germ slit extending the length of the spore. Asci 8-spored.
Similar species
Xylaria carpophila is similar but much more slender; it grows on rotting beech mast and is often buried in leaf litter.
Medicinal Properties
Antiviral activity
Polysaccharides extracted from dried fruit bodies of X. hypoxylon using hot water and alcohol precipitation were tested for inhibitory activity against HIV-reverse transcriptase by the colorimetric estimation method (using ELISA). The inhibitory activity of polysaccharides from X. hypoxylon at 1 mg/ml was 80.4 ± 1.2% (Liu et al., 2004).
Antitumor activity
The compound 19(βH), 20(αH)-epoxycytochalasin D (shown above) demonstrated potent cytotoxic activity against tumor cell line P-388 (Shi and Zhan, 2007). Additionally, a xylose-specific lectin isolated from the candlesnuff fungus showed antiproliferative and antitumor properties. This 28.8 kDa lectin has little amino acid sequence similarity to lectins from other ascomycete mushroom species such as Aspergillus oryzae or Aleuria aurantia. It also has unique carbohydrate-binding specificities, with a potent FeCl3 concentration-dependent hemagglutination property that was inhibited by xylose and inulin. The lectin’s antiproliferative properties towards tumor cell lines M1 and HepG2 was potent, with an IC50 <1µM (Liu et al., 2006).
Xylaria hypoxylon Chemical Compounds
A variety of chemical compounds within vitro properties have been identified in this fungus. The compounds xylarial A and B both have moderate cytotoxic activity against the human hepatocellular carcinoma cell line Hep G2. The pyrone derivative compounds named xylarone and 8,9-dehydroxylarone also have cytotoxic activity. Several cytochalasins, compounds that bind to actin in muscle tissue, have been found in the fungus. X. hypoxylon also contains a carbohydrate-binding protein, a lectin, with a unique sugar specificity, and which has potent anti-tumor effects in various tumor cell lines.
History
The scientific name Clavaria hypoxylon was given to this ascomycetous fungus in 1753 by Carl Linnaeus, but its currently accepted name Xylaria polymorpha dates from 1824, when Scottish mycologist and illustrator Robert Kaye Greville (1794 - 1866) transferred Dead Man's Fingers to the genus Xylaria.
Synonyms of Xylaria hypoxylon include Clavaria hypoxylon L., Sphaeria hypoxylon (L.) Pers., Sphaeria ramosa Dicks., and Xylosphaera hypoxylon (L.) Dumort.
The genus name Xylaria comes from the Greek noun Xýlon meaning wood - from the same source as the word xylem, which is the wood of a tree that transports water and nutrients from the roots up to the branches, twigs and leaves. The specific epithet hypoxylon comes from hypo- meaning beneath (or less than) and -xylon meaning wood. As you see, both the genus and species names make clear the subject of this rotter's desires.
Some people refer to this species as Carbon Antlers, and this seems just as apt as Candlesnuff Fungus - the latter being the common name promoted in the British Mycological Society's list of English Names of Fungi. Another name that you may see assigned to Xylaria hypoxylon in some older field guides is Stag's Horn Fungus, which could confuse with a similarly-shaped basidiomycete species Calocera viscosa, commonly known as Yellow Stagshorn.
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