MUSHROOM SERIES STARS OF THE GROUND – THE EARTHSTARS CHRIS HAY Email: [email protected] A specimen of Geastrum quadrifidum reported from La Ronge, SK (Sasata 2010). Note how the arms are reflexed to raise up the spore sac. The mycelial mat below is embedded with litter. “Earthstar” is an oxymoron; peridium splits apart in high hu- stars are in the sky, born in midity and opens up to form a the universe, not sitting on the star-like shape, while the inner ground having emerged from the peridium stays intact so an ordi- earth. But the Latin and Greek nary puffball sits inside. roots to their name, “Geastr”, mean exactly that: earth (Ge-, as The star serves a few pur- in ‘geography’) and star (astr-, as poses. Since the outer peridium in those starry ‘aster’ flowers). only opens at maturity and in Earthstars are basically a fancy wet conditions, the spores are puffball with two layers: the outer only released when they are fully 73 (3) September 2015 143 formed and have the best chance to be connected to the ground for germination, otherwise the at all. Apparently some can roll inner spore sac is shielded and around like tumbleweed after spore release is prevented. they are fully grown (in dry con- Some earthstars will only do ditions when closed). My earth- this once. Others can open and stars were completely dry, closed close multiple times, such as the like a tight fist as David Arora well-known earthstar Astraeus would describe (Arora 1986). hygrometricus known as the wa- When I got home I put them in a ter measurer or barometer earth- bowl of shallow water, and sure star (hygr- meaning moisture or enough when I checked a few humidity, metr- for metric, mea- minutes later they had opened! suring) (Arora 1986). I played with them, tapping the spore sac inside and watching Often the points of opened stars the little brown eruptions. My sis- will reflex, propping up the spore ter was horrified. sac with the arms of the star act- ing like stilts. The added height Like most fungi, taxonomy of of a couple centimeters above earthstars is in a process of cor- ground level can substantially rection in recent years. Though improve spore dispersal. Geast- earthstars would seem to all be rum quadrifidum (four-armed closely related, convergent evo- earthstar) is known for this dra- lution has apparently taken place matic ballerina-like pose. The for this morphological form. The epithet fits the common name genus Geastrum sits next to (quadr- fourfold, fid- divided) but stinkhorns, corals, and Gomphus sometimes the star splits five (wooly chanterelle) in the gom- ways. This species also has a lit- phoid-phalloid clade on the fun- tle support stalk below the spore gus phylogenetic tree of life (Pine sac and a distinct beak around et al. 1999). Meanwhile Astraeus the mouth area (peristome) (Bar- earthstars are more closely re- ron 1999). lated with boletes (fleshy mush- rooms with pores instead of gills). I remember years ago when I Michael Kuo insists there must encountered earthstars for the be an ecological reason for these first time. I was in a pine stand strange groupings (Kuo 2004). and they were scattered all over Perhaps both Astraeus and bo- the needle bed on the ground. It letes have always been fond of looked like someone dropped a associating with pine roots. The basket of them; they didn’t seem ecology theory seems like a rea- sonable idea to me but hasn’t 144 Blue Jay been studied yet. It is likely there REFERENCES aren’t enough collections or eco- logical notes associated with Arora D. (1986) Mushrooms De- them. mystified. 2nd Ed. Ten Speed Press, Berkeley, California. Earthstar taxonomy has also had amendments at the species Barron G. (1999) Mushrooms of level. Astraeus hygrometricus Ontario and Eastern Canada. used to be considered a wide- Lone Pine Publishing, Edmon- spread species across the globe, ton, Alberta. p. 91-96 but has since been split into sev- eral different species. Luckily Kuo, M. (2004) The Phallales. many of these phylogenetic di- Retrieved from the MushroomEx- visions correspond directly with pert.Com Web site: http://www. geography, such as the newly mushroomexpert.com/phallales. created species A. morganii en- html compassing North American col- lections of “A. hygrometricus” Phosri C, Martín MP, Watling (Phosri et al. 2013). Other spe- R. 2013. Astraeus: hidden di- cies from this split are found ex- mensions. IMA Fungus 4(2): clusively in Europe or Asia. 347–356. doi:10.5598/imafun- gus.2013.04.02.13 Earthstars are often found in areas with sandy soil and near Pine EM, Hibbett D, Donoghue trees (either hardwood or coni- MJ. 1999. Phylogenetic relation- fer). After you find them once, ships of cantharelloid and clavar- you will know when you are in ioid Homobasidiomycetes based the right area. When you see on mitochondrial and nuclear one, count the number of rays rDNA sequences. Mycologia 91: on the star, see if the spore sac 944-963. has a beak and a stalk, and real- ly, note anything else interesting Sasata, R. 2010. Geastrum and unique about it. If you are in quadrifidum Pers. (46881). http:// an area where collection is per- mushroomobserver.org/46881 mitted, take one home! You can [Photo redistributed under CC do the barometer test and see if BY-SA 3.0 license. URI: <http:// it continues to open and close. creativecommons.org/licenses/ At the least, your specimen will by-sa/3.0/> Image URL: <http:// make an interesting conversation images.mushroomobserver.org/ piece on your mantle. orig/89495.jpg>] 73 (3) September 2015 145.