Collybia tuberosa, the mushroom-loving Collybia. It's my 90th Fungus of the Month! Please click TomVolkFungi.net for the rest of Tom Volk's pages on fungi This month's fungus is Collybia tuberosa, a parasite on another mushroom, and one of only four species left in the genus Collybia. (Oh no! -- not another big genus change... ) --- but we'll get to the taxonomy later. Collybia tuberosa is a very common but often overlooked little white mushroom (LWM). According to Roy Halling (1997) it is often found growing on the remains of the fruiting bodies (mushrooms) of "...old agarics, polypores, hydnums, and boletes." It is difficult to determine the exact host species because by the time the Collybia fruits, the host mushroom is rotting, black and degraded, lacking the morphological features necessary for accurate identification. It has not been strictly proven that Collybia acts as a parasite of the host mushroom while it is still alive; it may be that it only grows on mushrooms that are already rotting. More work needs to be done on this. There are, of course, many other mycoparasitic fungi, including Entoloma abortivum on Armillaria gallica and related species, Psathyrella epimyces on Coprinus comatus, Spinellus fusiger on Mycena species, Tremella mesenterica on Stereum spp., Hypomyces lactifluorum on Russula and Lactarius species, Cordyceps ophioglossoides on Elaphomyces, and many others. In fact I gave an interesting (or so they said) lecture on these "cannibalistic" fungi at the 2001 NEMF foray in Massachusetts. Above you can see some fruiting bodies of Collybia tuberosa. Notice the appleseed-shaped sclerotia at the base of the stipe. These sclerotia are hard, thick-walled, resistant resting structures that allow the fungus to overwinter. More of these sclerotia are visible in "A" below. Neither the mushrooms nor the sclerotia are known to be edible, although no poisoning have been reported. They're just really too small to collect for the table. So, what about the taxonomy of Collybia? In the olden days, the genus Collybia was very broadly defined and included many more species than it does today. The genus Collybia was once a taxonomic refugium for mushrooms that had white spores, attached gills, no annulus, with somewhat straight stipes and a rather cartilaginous texture. However, once mycologists started to look more closely at the microscopic features of the mushrooms, it became clear that there was a great variation in gill structure (in particular the arrangement of the cells in the trama, or gill flesh) and in the pileipellis (cap cuticle), which indicated that Collybia should be split into several genera. In 1983, Roy Halling of the New York Botanical Garden published "The genus Collybia (Agaricales) in the Northeastern United States and adjacent Canada," Mycologia Memoirs 8: 1-148. However, there are many common species that were long ago kicked out of Collybia The common species Flammulina velutipes (a.k.a. the winter mushroom, velvet stem or enokitake, =C in the picture to the right) was once known as Collybia velutipes. The genus Flammulina was segregated from Collybia because of the structure of the pileipellis (which in this case results in a slimy texture) and the presence of large cystidia (sterile cells) on the gills. Another common species Megacollybia platyphylla (a.k.a. the platterful mushroom =B) has been segregated because of its growth habit on wood, non-radicating stipe with white rhizomorphs at the base, and having gills that are adnexed (notched or barely attached). Xerula radicata (=E, with Heather Hallen) is another former Collybia. It has undergone several changes in its name in the past 35 years-- I can usually tell how long ago someone learned mycology by whether they think of the species as Collybia radicata, Oudemansiella radicata or Xerula radicata. Collybia radicata was first placed in Oudemansiella because of its radicating (root-like) stem. However, once Scott Redhead and others began looking more closely at this mushroom, they discovered that true Oudemansiella species are usually slimy and lack thick walled skeletal hyphae in their fruiting bodies, while Xerula species are dry (hence the name) and are sarcodimitic-- i.e. they contain thick walled skeletal hyphae in their fruiting bodies, as many polypores do. You can read more about hyphal structure on my polypore page. No one is suggesting that Xerula species are related to the polypores-- there are too many significant differences. However convergent evolution has seemed to produce thick-walled hyphae several times in several different evolutionary lines. In 1987 Redhead, Ginns and Shoemaker ["The Xerula (Collybia, Oudemansiella) radicata complex in Canada" Mycotaxon 30: 357-405] clarified the species concepts of Xerula and delimited several additional species in that genus. I'll probably have to make Xerula the Fungus of the Month someday, but this will do for now. In 1997, Vladimir Antonín, Roy Halling, and M. E. Noordeloos [Generic concepts within the groups Marasmius and Collybia sensu lato. Mycotaxon 63: 359-368] revised the taxonomy of Collybia sensu lato (in the broad sense), recognizing that there should be three genera. It became apparent from their study of the remaining Collybia species that three genera are represented; there are many differences in trama and pileipellis structure and even in spore color that warrant the splitting of Collybia into three very distinct genera, one of which contained the bulk of the familiar species and two of which had relatively few species. It was apparent that two more genus names were needed, but what should they be called? It would certainly be the easiest and most convenient course of action to choose the course of action that entail the fewest possible number of name changes-- that is, the fewest number of changes that the rules would allow. However, it remained unclear which genus should retain the name Collybia. Fortunately there are very strict rules for naming species and for deciding which names to apply to certain fungi. The revision (=split) of the genus Collybia is based on Collybia tuberosa being named the type species of the genus Collybia. The International Code of Botanical Nomenclature defines the type species: Art. 7.2. A nomenclatural type (typus) is that element to which the name of a taxon is permanently attached, whether as a correct name or as a synonym. The nomenclatural type is not necessarily the most typical or representative element of a taxon. Art. 10.1. The type of a name of a genus or of any subdivision of a genus is the type of a name of a species (except as provided by Art. 10.4). For purposes of designation or citation of a type, the species name alone suffices, i.e., it is considered as the full equivalent of its type. When Collybia tuberosa was conserved and confirmed as the type species, the genus Collybia thus became restricted to rather small mycoparasitic fungi. This is unfortunate for those who want to learn names, because it is the scenario that requires the largest number of name changes. Oh well... Since keeping the genus name Collybia for all the species was not a viable (or taxonomically legal) option, Vladimir Antonín et al. searched the literature for genus names for the other two genera and found that several other mycologists had already noted these differnces. They came up with Gymnopus and Rhodocollybia for the . Gymnopus (Pers.) Roussel was described as a subgenus of Agaricus by Persoon, then elevated to generic status by Roussel in 1806 (Fl. Calavad. ed 2. 62). Its type species is Gymnopus fusipes, a strictly European species. Rhodocollybia Singer was described by Rolf Singer in 1939 (Schweiz. Zeit. Pilzk. 17: 71). Fortunately Roy Halling has updated his 1983 book with the revised taxonomy online at http://www.nybg.org/bsci/res/col as "A revision of Collybia s.l. in the northeastern United States and adjacent Canada." You can read more about the morphological differences that created the taxonomic problems there. I'll briefly distinguish between the genera here: Collybia in the strict sense (sensu stricto) is now restricted to four known species: C. tuberosa, C. cookei, C. racemosa, and C. cirrhata, all of which are usually found growing on other mushrooms. They are all very small (<20 mm diameter) with basidiospores usually less than 6µm in length. Gymnopus (not to be confused with Gymnopilus, which has rusty brown spores) has a much larger pileus (cap), almost always >20mm diameter when mature, usually much larger. The basidiospores are larger, usually greater than 6µm in length. The fruiting bodies are often cartilaginous in texture. There are at least 30 species. See "F" above for photo of Gymnopus dryophilus. Rhodocollybia is the most different of the three genera. Its spore print is "pinkish cream to pinkish buff when fresh." Microscopically the basidiospores are dextrinoid (brown-red in Melzer's reagent, which is mostly iodine) and cyanophilous (absorbing the dye "cotton blue"). The fruiting bodies are normally more fleshy and rot more easily. There are about 8 species. See "D" above for photo of Rhodocollybia maculata, named for its abundant spots. It is easy to remember the genus name because of the pink spores and red color in Melzer's-- "rhodo" is the Greek word for red. The split of Collybia into these several genera has been well accepted by mycologists, although on a practical level sometimes it's difficult to change the names of fungi with which you're familiar. But you can do it...! I hope you enjoyed learning something about Collybia tuberosa and friends. Try out your newfound knowledge at your next foray or mycological event! See if you can find any other mycoparasitic fungi. There are many interesting ones out there! If you have anything to add, or if you have corrections, comments, or recommendations for future FotM's (or maybe you'd like to be co-author of a FotM?), please write to me at volk.thom@uwlax.edu This page and other pages are © Copyright 2004 by Thomas J. Volk, University of Wisconsin-La Crosse. Learn more about fungi! Go to Tom Volk's Fungi Home Page --TomVolkFungi.net Return to Tom Volk's Fungus of the month pages listing
Please click TomVolkFungi.net for the rest of Tom Volk's pages on fungi
This month's fungus is Collybia tuberosa, a parasite on another mushroom, and one of only four species left in the genus Collybia. (Oh no! -- not another big genus change... ) --- but we'll get to the taxonomy later. Collybia tuberosa is a very common but often overlooked little white mushroom (LWM). According to Roy Halling (1997) it is often found growing on the remains of the fruiting bodies (mushrooms) of "...old agarics, polypores, hydnums, and boletes." It is difficult to determine the exact host species because by the time the Collybia fruits, the host mushroom is rotting, black and degraded, lacking the morphological features necessary for accurate identification. It has not been strictly proven that Collybia acts as a parasite of the host mushroom while it is still alive; it may be that it only grows on mushrooms that are already rotting. More work needs to be done on this. There are, of course, many other mycoparasitic fungi, including Entoloma abortivum on Armillaria gallica and related species, Psathyrella epimyces on Coprinus comatus, Spinellus fusiger on Mycena species, Tremella mesenterica on Stereum spp., Hypomyces lactifluorum on Russula and Lactarius species, Cordyceps ophioglossoides on Elaphomyces, and many others. In fact I gave an interesting (or so they said) lecture on these "cannibalistic" fungi at the 2001 NEMF foray in Massachusetts. Above you can see some fruiting bodies of Collybia tuberosa. Notice the appleseed-shaped sclerotia at the base of the stipe. These sclerotia are hard, thick-walled, resistant resting structures that allow the fungus to overwinter. More of these sclerotia are visible in "A" below. Neither the mushrooms nor the sclerotia are known to be edible, although no poisoning have been reported. They're just really too small to collect for the table. So, what about the taxonomy of Collybia? In the olden days, the genus Collybia was very broadly defined and included many more species than it does today. The genus Collybia was once a taxonomic refugium for mushrooms that had white spores, attached gills, no annulus, with somewhat straight stipes and a rather cartilaginous texture. However, once mycologists started to look more closely at the microscopic features of the mushrooms, it became clear that there was a great variation in gill structure (in particular the arrangement of the cells in the trama, or gill flesh) and in the pileipellis (cap cuticle), which indicated that Collybia should be split into several genera. In 1983, Roy Halling of the New York Botanical Garden published "The genus Collybia (Agaricales) in the Northeastern United States and adjacent Canada," Mycologia Memoirs 8: 1-148. However, there are many common species that were long ago kicked out of Collybia The common species Flammulina velutipes (a.k.a. the winter mushroom, velvet stem or enokitake, =C in the picture to the right) was once known as Collybia velutipes. The genus Flammulina was segregated from Collybia because of the structure of the pileipellis (which in this case results in a slimy texture) and the presence of large cystidia (sterile cells) on the gills. Another common species Megacollybia platyphylla (a.k.a. the platterful mushroom =B) has been segregated because of its growth habit on wood, non-radicating stipe with white rhizomorphs at the base, and having gills that are adnexed (notched or barely attached). Xerula radicata (=E, with Heather Hallen) is another former Collybia. It has undergone several changes in its name in the past 35 years-- I can usually tell how long ago someone learned mycology by whether they think of the species as Collybia radicata, Oudemansiella radicata or Xerula radicata. Collybia radicata was first placed in Oudemansiella because of its radicating (root-like) stem. However, once Scott Redhead and others began looking more closely at this mushroom, they discovered that true Oudemansiella species are usually slimy and lack thick walled skeletal hyphae in their fruiting bodies, while Xerula species are dry (hence the name) and are sarcodimitic-- i.e. they contain thick walled skeletal hyphae in their fruiting bodies, as many polypores do. You can read more about hyphal structure on my polypore page. No one is suggesting that Xerula species are related to the polypores-- there are too many significant differences. However convergent evolution has seemed to produce thick-walled hyphae several times in several different evolutionary lines. In 1987 Redhead, Ginns and Shoemaker ["The Xerula (Collybia, Oudemansiella) radicata complex in Canada" Mycotaxon 30: 357-405] clarified the species concepts of Xerula and delimited several additional species in that genus. I'll probably have to make Xerula the Fungus of the Month someday, but this will do for now. In 1997, Vladimir Antonín, Roy Halling, and M. E. Noordeloos [Generic concepts within the groups Marasmius and Collybia sensu lato. Mycotaxon 63: 359-368] revised the taxonomy of Collybia sensu lato (in the broad sense), recognizing that there should be three genera. It became apparent from their study of the remaining Collybia species that three genera are represented; there are many differences in trama and pileipellis structure and even in spore color that warrant the splitting of Collybia into three very distinct genera, one of which contained the bulk of the familiar species and two of which had relatively few species. It was apparent that two more genus names were needed, but what should they be called? It would certainly be the easiest and most convenient course of action to choose the course of action that entail the fewest possible number of name changes-- that is, the fewest number of changes that the rules would allow. However, it remained unclear which genus should retain the name Collybia. Fortunately there are very strict rules for naming species and for deciding which names to apply to certain fungi. The revision (=split) of the genus Collybia is based on Collybia tuberosa being named the type species of the genus Collybia. The International Code of Botanical Nomenclature defines the type species: Art. 7.2. A nomenclatural type (typus) is that element to which the name of a taxon is permanently attached, whether as a correct name or as a synonym. The nomenclatural type is not necessarily the most typical or representative element of a taxon. Art. 10.1. The type of a name of a genus or of any subdivision of a genus is the type of a name of a species (except as provided by Art. 10.4). For purposes of designation or citation of a type, the species name alone suffices, i.e., it is considered as the full equivalent of its type. When Collybia tuberosa was conserved and confirmed as the type species, the genus Collybia thus became restricted to rather small mycoparasitic fungi. This is unfortunate for those who want to learn names, because it is the scenario that requires the largest number of name changes. Oh well... Since keeping the genus name Collybia for all the species was not a viable (or taxonomically legal) option, Vladimir Antonín et al. searched the literature for genus names for the other two genera and found that several other mycologists had already noted these differnces. They came up with Gymnopus and Rhodocollybia for the . Gymnopus (Pers.) Roussel was described as a subgenus of Agaricus by Persoon, then elevated to generic status by Roussel in 1806 (Fl. Calavad. ed 2. 62). Its type species is Gymnopus fusipes, a strictly European species. Rhodocollybia Singer was described by Rolf Singer in 1939 (Schweiz. Zeit. Pilzk. 17: 71). Fortunately Roy Halling has updated his 1983 book with the revised taxonomy online at http://www.nybg.org/bsci/res/col as "A revision of Collybia s.l. in the northeastern United States and adjacent Canada." You can read more about the morphological differences that created the taxonomic problems there. I'll briefly distinguish between the genera here: Collybia in the strict sense (sensu stricto) is now restricted to four known species: C. tuberosa, C. cookei, C. racemosa, and C. cirrhata, all of which are usually found growing on other mushrooms. They are all very small (<20 mm diameter) with basidiospores usually less than 6µm in length. Gymnopus (not to be confused with Gymnopilus, which has rusty brown spores) has a much larger pileus (cap), almost always >20mm diameter when mature, usually much larger. The basidiospores are larger, usually greater than 6µm in length. The fruiting bodies are often cartilaginous in texture. There are at least 30 species. See "F" above for photo of Gymnopus dryophilus. Rhodocollybia is the most different of the three genera. Its spore print is "pinkish cream to pinkish buff when fresh." Microscopically the basidiospores are dextrinoid (brown-red in Melzer's reagent, which is mostly iodine) and cyanophilous (absorbing the dye "cotton blue"). The fruiting bodies are normally more fleshy and rot more easily. There are about 8 species. See "D" above for photo of Rhodocollybia maculata, named for its abundant spots. It is easy to remember the genus name because of the pink spores and red color in Melzer's-- "rhodo" is the Greek word for red. The split of Collybia into these several genera has been well accepted by mycologists, although on a practical level sometimes it's difficult to change the names of fungi with which you're familiar. But you can do it...! I hope you enjoyed learning something about Collybia tuberosa and friends. Try out your newfound knowledge at your next foray or mycological event! See if you can find any other mycoparasitic fungi. There are many interesting ones out there! If you have anything to add, or if you have corrections, comments, or recommendations for future FotM's (or maybe you'd like to be co-author of a FotM?), please write to me at volk.thom@uwlax.edu This page and other pages are © Copyright 2004 by Thomas J. Volk, University of Wisconsin-La Crosse. Learn more about fungi! Go to Tom Volk's Fungi Home Page --TomVolkFungi.net Return to Tom Volk's Fungus of the month pages listing
There are, of course, many other mycoparasitic fungi, including Entoloma abortivum on Armillaria gallica and related species, Psathyrella epimyces on Coprinus comatus, Spinellus fusiger on Mycena species, Tremella mesenterica on Stereum spp., Hypomyces lactifluorum on Russula and Lactarius species, Cordyceps ophioglossoides on Elaphomyces, and many others. In fact I gave an interesting (or so they said) lecture on these "cannibalistic" fungi at the 2001 NEMF foray in Massachusetts.
Above you can see some fruiting bodies of Collybia tuberosa. Notice the appleseed-shaped sclerotia at the base of the stipe. These sclerotia are hard, thick-walled, resistant resting structures that allow the fungus to overwinter. More of these sclerotia are visible in "A" below. Neither the mushrooms nor the sclerotia are known to be edible, although no poisoning have been reported. They're just really too small to collect for the table.
So, what about the taxonomy of Collybia? In the olden days, the genus Collybia was very broadly defined and included many more species than it does today. The genus Collybia was once a taxonomic refugium for mushrooms that had white spores, attached gills, no annulus, with somewhat straight stipes and a rather cartilaginous texture. However, once mycologists started to look more closely at the microscopic features of the mushrooms, it became clear that there was a great variation in gill structure (in particular the arrangement of the cells in the trama, or gill flesh) and in the pileipellis (cap cuticle), which indicated that Collybia should be split into several genera. In 1983, Roy Halling of the New York Botanical Garden published "The genus Collybia (Agaricales) in the Northeastern United States and adjacent Canada," Mycologia Memoirs 8: 1-148. However, there are many common species that were long ago kicked out of Collybia
The common species Flammulina velutipes (a.k.a. the winter mushroom, velvet stem or enokitake, =C in the picture to the right) was once known as Collybia velutipes. The genus Flammulina was segregated from Collybia because of the structure of the pileipellis (which in this case results in a slimy texture) and the presence of large cystidia (sterile cells) on the gills.
In 1997, Vladimir Antonín, Roy Halling, and M. E. Noordeloos [Generic concepts within the groups Marasmius and Collybia sensu lato. Mycotaxon 63: 359-368] revised the taxonomy of Collybia sensu lato (in the broad sense), recognizing that there should be three genera. It became apparent from their study of the remaining Collybia species that three genera are represented; there are many differences in trama and pileipellis structure and even in spore color that warrant the splitting of Collybia into three very distinct genera, one of which contained the bulk of the familiar species and two of which had relatively few species. It was apparent that two more genus names were needed, but what should they be called? It would certainly be the easiest and most convenient course of action to choose the course of action that entail the fewest possible number of name changes-- that is, the fewest number of changes that the rules would allow. However, it remained unclear which genus should retain the name Collybia.
Fortunately there are very strict rules for naming species and for deciding which names to apply to certain fungi. The revision (=split) of the genus Collybia is based on Collybia tuberosa being named the type species of the genus Collybia. The International Code of Botanical Nomenclature defines the type species:
When Collybia tuberosa was conserved and confirmed as the type species, the genus Collybia thus became restricted to rather small mycoparasitic fungi. This is unfortunate for those who want to learn names, because it is the scenario that requires the largest number of name changes. Oh well...
Since keeping the genus name Collybia for all the species was not a viable (or taxonomically legal) option, Vladimir Antonín et al. searched the literature for genus names for the other two genera and found that several other mycologists had already noted these differnces. They came up with Gymnopus and Rhodocollybia for the . Gymnopus (Pers.) Roussel was described as a subgenus of Agaricus by Persoon, then elevated to generic status by Roussel in 1806 (Fl. Calavad. ed 2. 62). Its type species is Gymnopus fusipes, a strictly European species. Rhodocollybia Singer was described by Rolf Singer in 1939 (Schweiz. Zeit. Pilzk. 17: 71). Fortunately Roy Halling has updated his 1983 book with the revised taxonomy online at http://www.nybg.org/bsci/res/col as "A revision of Collybia s.l. in the northeastern United States and adjacent Canada." You can read more about the morphological differences that created the taxonomic problems there. I'll briefly distinguish between the genera here:
I hope you enjoyed learning something about Collybia tuberosa and friends. Try out your newfound knowledge at your next foray or mycological event! See if you can find any other mycoparasitic fungi. There are many interesting ones out there!
Learn more about fungi! Go to Tom Volk's Fungi Home Page --TomVolkFungi.net
Return to Tom Volk's Fungus of the month pages listing
