Cyathus striatus
Description
Cyathus striatus is a saprobic basidiomycete that grows on decaying forest litter or on wood chips. It is widely distributed and can be commonly found in urban areas due to its ability to grow on wood chips.
The fruiting body contains peridioles which give the fungus it’s common name (Fluted Bird’s Nest), by making it appear as though the fruiting body is a nest containing eggs. Before maturity, the “nest” of the fruiting body is covered by a white lid that later disappears, revealing the peridioles.
All of the bird’s nest fungi look like miniature nests (generally only ¼ inch in diameter) filled with four or five tiny eggs.
The “eggs” are disc-shaped bodies called peridioles that contain basidiospores. C. striatus has rough, shaggy, or hairy exterior and smooth but grooved inner cup walls, features that easily distinguished it from other similar bird’s nest fungi. This species varies somewhat in size and color from a bright orange-brown to dark grey or dull brown, darkening with age.
The peridioles vary in color from gray-white through various shades of brown to almost black.
If the basidiospores released from the peridioles land on suitable wood or bark, generally in damp and shady spots, they germinate and produce new mycelium that infiltrates the wood or bark. Eventually, when conditions are appropriate, that mycelium grows into new fruiting bodies.
The immature nests are covered by a thin membrane called an epiphragm. Eventually, this lid degrades once the peridioles are ripe, opening up the cup to expose the “eggs”, so that rain can splash them out to continue the cycle. The cups are very tough and persistent, so remain in the environment well after the “eggs” are splashed away.
Common names: Fluted Bird’s Nest.
Mushroom Identification
Ecology
Saprobic; growing scattered or gregariously on forest debris in open woods, but rarely terrestrial; sometimes on woodchips; summer and fall; widely distributed in North America.
Nest
Typically 7–10 mm high and 6–8 mm wide, but variable in size; vase-shaped; outer surface grayish buff to dark brown, shaggy to woolly, with tufts of hairs; inner surface distinctly grooved or lined (otherwise bald) and shiny; "lid" typically white, disappearing with maturity.
Eggs
To 2 mm wide; ellipsoid, or often roughly triangular; sheathed; attached to the nest by cords (funiculi).
Similar species
Cyathus stercoreus is very similar (its rim is not so widely flared, however) but its peridioles are much smaller, and sometimes as many as 20 are produced in one peridium; it is a dung-loving species (the specific epithet stercoreus means 'filth') but is also found on marram grass in coastal sand dunes.
Several similar species occur throughout Europe. Cyathus olla (without ribbed nest walls) and Crucibulum laeve are fairly common (but equally hard to spot) in Britain and Ireland as well as on mainland Europe and further afield.
Medicinal Properties
Antibiotic activity
The mycelia and cultural filtrates of C. striatus were tested for antibiotic activity against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Salmonella typhimurium and Candida albicans. C. striatus was shown to have antibacterial activity against B. cereus and B. subtilis (Colletto and Giardino, 1996).
Antibiotics named striatins A, B, and C have been isolated from the mycelium of Cyathus striatus. The striatins are active against a variety of Gram-positive bacteria, some Gram-negative bacteria, and highly active against fungi imperfecti (Anke and Oberwinkler, 1977). The chemical structures of these antibiotics have been elaborated using X-ray crystallography (Hecht et al., 1978). A later study investigated the optimization of striatin production using fermentation technology (Gehrig et al., 1998). Striatins A and B were tested in culture media against various forms of Leishmania species and Trypanosoma cruzi. These protozoa cause diseases that are responsible for considerable mortality and morbidity, especially in tropical areas. Striatins A and B showed in vitro activity at 10 and 5 µg/ml, respectively. BALB/c mice infected with Leishmania amazonensis were treated 3 weeks post-infection with striatins A or B (daily dose of 10 mg/kg, subcutaneously, for 15 days). Treatment with the reference drug, N-methylglucamine antimonite (an anti-leishmanial drug with known properties), reduced the parasite burden by 71.2%. Treatment with striatin A slightly decreased the parasite burden in the footpad by 17.6%; treatment with striatin B had no effect and was more toxic than striatin A (Inchausti et al., 1997).
Anti-cancer effects
NF-kB (nuclear factor kappa B) is a protein complex that is involved in regulating the immune response to infection. Alterations in the body’s response to NF-kB has been implicated in the pathology of various diseases, including cancer. For instance, it is known that in several human cancers, the NF-kB gene regulation pathway is always turned on, disrupting normal gene expression patterns and enabling some cells to survive in conditions where others would die. Fungal extracts prepared from Cyathus striatus showed significant inhibitory effects on the NF-kB activation pathway, suggesting activities worthy of investigation as cancer therapeutics (Petrova et al. 2006).
Cyathus striatus Bioactive compounds
Cyathus striatus has proven to be a rich source of bioactive chemical compounds. It was first reported in 1971 to produce "indolic" substances (compounds with an indole ring structure) as well as a complex of diterpenoid antibiotic compounds collectively known as cyathins. Several years later, research revealed the indolic substances to be compounds now known as striatins. Striatins (A, B and C) have antibiotic activity against fungi imperfecti, and various Gram-positive and Gram-negative bacteria. C. striatus also produces sesquiterpene compounds called schizandronols. It also contains the triterpene compounds glochidone, glochidonol, glochidiol and glochidiol diacetate, cyathic acid, striatic acid, cyathadonic acid and epistriatic acid. The latter four compounds were unknown prior to their isolation from C. striatus.
History
The Fluted Bird's Nest was described in 1778 by British mycologist William Hudson (1730 - 1793), who called it Peziza striata (effectively placing it within a group of ascomycete cup fungi, whereas this and the various other bird's nest fungi are, of course, basidiomycete species). It was Christiaan Hendrik Persoon who, in 1801, transferred this species to the genus Cyathus, creating its current scientific name Cyathus striatus.
Synonyms of Cyathus striatus include Peziza striata Huds., Nidularia striata (Huds.) With., and Cyathella striata (Huds.) Brot.
The generic name Cyathus comes from the Greek prefix kyath- meaning cup shaped (like a chalice). Even more obvious is the meaning of the specific epithet striatus, which refers to the striate or striped (ribbed) sides of the cups of these remarkable little fungi.
Photo sources:
Photo 1 - Author: Andrea Westmoreland from DeLand, United States (CC BY-SA 2.0)
Photo 2 - Author: Christian Grenier (Public Domain)
Photo 3 - Author: Björn S... (CC BY-SA 2.0)
Photo 4 - Author: Cole Shoemaker (CC BY-SA 4.0)
Photo 5 - Author: John Roper (madjack74) (CC BY-SA 3.0)
