Photo by Billy Stone
The 2006 New Mexico mushroom season came to an interesting end with the appearance in mid-September of this odd little organism (photo above) in the grassland around our home near Ribera, New Mexico. They popped up just like regular mushrooms but they had no outer skin or membrane, no internal structure, or any other obvious means of holding themselves together. They just look like dark little balls of dirt. They crumble into a kind of oily dust between your fingers when dry (which they usually are, around here) and are kind of spongy-crumbly, like cake, when they’re wet. They did not seem to “fit” anywhere in any of the usual mushroom literature, and had my mycological friends and me scratching our heads wondering what they were.
Intrepid New Mexico Mycological Society member Ted Stampfer finally asked Dr. Jim Trappe of Oregon State University, the North American authority on truffles and other things hypogeous (below ground), who suggested that they might belong to the recently-erected fungal Class Glomeromycetes, which are known as Arbuscular Mycorrhizal Fungi or AMF (formerly also called Vesicular-Arbuscular Mycorrhizal fungi or VAM fungi). Most of these form symbiotic associations with plants. We sent him some specimens and this led to a lengthy and as yet incomplete story.
On November 25, 2006, Dr. Trappe responded that this was the first time he had seen the species since he examined the type collection, and that the mystery fungus was Acaulospora sporocarpia, originally described in 1985 by Shannon Berch (Mycotaxon 23: 409-418) from a collection made in 1955 from “a borrowed pit 40 miles SW of Winslow, Arizona.” collected by D.J. Stouffer, New Mexico . There was also one collection known from Pakistan, but he noted that the Pakistan material, however, differed in several ways and probably was a different species. He wrote that it evidently is a species of arid lands and is rarely collected, and speculated that it may be common but overlooked.
Dr. Trappe then forwarded two of the specimens to Dr. Chris Walker in England, the world authority on this and related genera for an opinion and in the hope that it could be tested to see if it was indeed a mycorrhizal fungus. He also expressed interest in receiving any other hypogeous fungi from the area because few collections had been made in New Mexico, but there must surely be plenty of such species, many that would be unusual or new to science.
Later that month, Dr. Walker responded, expressing interest, and even excitement about the find of Acaulospora sporocarpia. He pointed out that the fungus, from the original description, is unlike any other in the genus, or even in the entire phylum . The chance of establishing a culture was discussed, and it was pointed out that if it is really an Acaulospora, it would have to be grown in symbiosis with a plant. He also thought it might be possible to extract DNA to examine its phylogenetic position in relation to other members of the phylum.
In December, Dr. Walker wrote again, confirming the identity of the fungus, and explaining that the reason he was so interested in the specimens of Acaulospora sporocarpia was because the only other record he knew of was the original collection, and this was only the second time the organism has been collected. Being relatively fresh, it therefore was the only material that has any chance of still being alive, and therefore is very important in that such material has a better chance of containing good quality DNA suitable for study than the old, long-dried herbarium material of the past. If it were possible to extract DNA, then this collection could be instrumental in answering the question of whether or not A. sporocarpia really belongs to the genus. It is the only sporocarpic (that is, forming its spores in something approaching a ‘spore body’, rather than singly in the soil) member of the entire order, and it therefore raised his suspicions that, even if it did prove to belong with the AMF, it perhaps would belong in a different (and new) genus.
Unfortunately, after several attempts, there was only failure in trying to establish mycorrhizas with spores of A. sporocarpia as inoculum, and it had not been possible to extract DNA with the methods available. Dr. Walker wondered if failure to establish pot cultures might be because they are host-specific, or perhaps they require soil more like that of New Mexico or Arizona soil. So, it all is a bit mysterious.
By June, 2007, it was clear that not only was it impossible to establish cultures, but DNA extraction also had failed. Dr. Walker suggested digging up some Bouteloua, complete with roots, and very thoroughly washing away all the soil and any attached decaying vegetation, and planting them up in pots containing sterilized local soil and examining them after some months (at least three) to see if the fungus sporulated in the substrate. He noted that the fungi in this phylum are difficult to work with, and many had taken more than a decade to sort out.
Habitat: Solitary to scattered, occasionally two found contiguous or conjoined, in open, sandy, predominantly blue grama (Bouteloua gracilis) grassland soil (pH=7.3 +/-) in Piñon/Juniper woodlands, up to 10 meters ouside of tree drip-line. Not noticed inside drip-line. Fruitbody forming cracked "mushrump" in soil, not extending more than 1-2 cm above edge of crack. Cracked soil settling down around fruitbody with rain, leaving fruitbody partially to fully free and exposed on the soil surface. Fruitbody persistent, slowly weathering down over time.
Description: Width: 1-2.5 x 1-2.5 cm, roughly circular. Height: 1.5-3.5 cm, rounded top, generally tapering, sometimes narrowly, to base. Fruitbody surface encrusted with soil, sometimes showing some pitting, no exterior membrane/peridium. No rooting structure. Crumbly with an oily, moss-like feel when dry, spongy when wet. Odor similar to linseed oil noticed after being enclosed in container. Interior blackish to reddish brown, apparently composed of sand and soil bound together with undifferentiated cellular network. When viewed with a hand lens, hyphae can be seen protruding from the surface, giving it a slightly velvety appearance, with shiny black spheres (spores) and grains of sand visible throughout. No visible columella or chambering.
Dr. Trappe sent us to Dr. Tom Bruns' website at UC Berkeley so we could download the 1974 article Dr. Trappe wrote with Dr. J.W. Gerdemann on
The Endogonaceae in the Pacific Northwest (15-mb pdf file), in which the genus Acaulospora is first described.
A really nice place to learn more about AM fungi is at Dr. Janusz Blaszkowski's website from the University of Agriculture in Szczecin, Poland.
Here's some food for thought...
"The study of plants without their mycorrhizas is the study of artefacts.
The majority of plants, strictly speaking, do not have roots; they have mycorrhizas."BEG Committee, 25th May, 1993
In September, 2011, I was asked to remove from this page any references to certain individuals and their participation in studying this organism.
Apparently, I was being seen by some as a sort of mycological Julian Assange, leaking state secrets or something. Perhaps I should rename this site to FungaLeaks. At any rate, the text above, kindly edited by Dr. Walker, reflects that request.
The text below takes a somewhat different approach to modifying this page from how it stood for almost five years.
The 2006 New Mexico mushroom season came to an interesting end with the appearance in mid-September of these odd little organisms (above) in the grassland around our home near Ribera, NM. They popped up just like regular mushrooms but they had no outer skin or membrane, no internal structure, or any other obvious means of holding themselves together. They just look like dark little balls of dirt. They crumble into a kind of oily dust between your fingers when they're dry (which they usually are, around here) and they're kind of spongy-crumbly, like cake, when they're wet. They didn't seem to "fit" anywhere in any of the usual mushroom literature, and had my mycological friends and me scratching our heads wondering what they were.
Intrepid NMMS member Ted Stampfer finally asked Dr. Jim Trappe of Oregon State University, the North American authority on truffles and other things hypogeous (belowground), who suggested that they might belong to the recently-erected fungal Class Glomeromycetes, which are known as Arbuscular Mycorrhizal Fungi or AMF (formerly called Vesicular-Arbuscular Mycorrhizae or VAM), fungi that form symbiotic associations with most plants. We sent him some specimens and thus began the communication below.
November 25, 2006 - This in from Dr. Trappe:
Your mystery fungus is Acaulospora sporocarpia, originally described in 1985 by Shannon Berch (Mycotaxon 23: 409-418) from Arizona 70 mi. S. of Winslow but also known from one collection from Pakistan. The Pakistan material, however, differs in several ways and probably should be a different species. I have never seen this species until your specimens arrived here. It evidently is a species of arid lands and is rarely collected (but it may be common but overlooked...keep your eagle eyes open for more).
I'm sending 2 of the specimens you sent to me to Dr. Chris Walker in England, the world authority on this and related genera. He will try to establish it in pot culture with a host plant and will send some toof
Thanks very much for contacting me about this find; I'll be keen to see any other hypogeous fungi you encounter, because not many collections have been made in New Mexico, but it must surely have plenty of species, many unusual or new.
November 27, 2006 - This arrived from Dr. Chris Walker:
I am rather excited about your find of Acaulospora sporocarpia (shows what a sad life we taxonomists live). This fungus is so unlike any other in the group that I really never quite believed the original description. I don't know how much chance there will be of establishing a culture (if it is really an Acaulospora, it will have to be grown with a plant). However, nothing ventured, nothing gained, as they say. Providing the material is not too old and dry, there may, however, be a good chance of extracting DNA, and I will send some away as soon as I can to
December 05, 2006 - More from Dr. Walker:
As to why I was so excited about your Acaulospora sporocarpia (assuming that is what it is), this is because the only other record I am aware of is the original collection...so, yours, I think, is only the second time this organism has been collected. It is the only material that has any chance of still being alive, and therefore is very important indeed. You will perhaps see from
March 09, 2007 - Dr. Walker reports:
I have a preliminary report back from
April 12, 2007 - Another report:
...we have so far had very disappointing results from our pot culturing efforts. I have checked two culture attempts in UK, and two in
June 01, 2007 - The latest report:
Not exciting news, I'm afraid. I was in
Somewhat confusing news in regard to the pot culture attempts. There is not even the slightest hint of mycorrhiza present in most of the cultures we have tried so far.
Well, we are in it for the long-haul, as they say. So I will keep plugging away. Here's an idea. Now that your Bouteloua will be growing nicely, dig some up, complete with roots, and very thoroughly wash away all the soil and any attached decaying vegetation. Then plant them up in pots containing sterilised substrate (you can sterilise some of your local soil in a microwave). After some months (at least 3) we can then see what has sporulated in the substrate, and also see what is in the roots by staining).
Sorry for all this doom and gloom. I had hoped we would have it all well sorted out by now, but this is the nature of research into AMF. Quite a lot of things have taken me more than a decade to sort out.
Contact: bolete at gmail dot com
This site was last updated on October 13, 2011. Thanks for visiting.