Details about map content are available here Click on the map dots to view record details.
Species Information
Summary: Features include 1) a spherical to somewhat pear-shaped fruitbody that develops underground, and opens up above ground as its thick wall splits into 4-8 star-like rays like a Geastrum species, exposing the spore mass, 2) absent stem but sometimes with rhizoids, 3) the surface whitish becoming brownish, covered with a layer of cottony mycelium when immature, then smooth to slightly cracked-scaly, with adherent particles of soil, 4) a spore mass that is dark brown with whitish and yellowish filaments, eventually powdery, 5) growth typically in sandy soil in pastures, and 6) round, slightly spiny subreticulate spores. It is rare in western North America. Note the large discrepancy in spore size between Guzman and Sims. Western material has more reticulate spores and could constitute a separate forma.
Collections were examined from OR, AL, CA, DC, DE, GA, IL, IN, OH, OK, KY, LA, MA, MD, MO, MS, NC, NJ, NY, PA, SC, TN, TX, VA, Algeria, Morocco, France, Italy, Portugal, Russia, Spain, Israel, Australia, New and Caledonia, (Guzman), and MI (Sims). The University of British Columbia has collections from BC (as Scleroderma geaster) and Pacific Forestry Center has another from BC (as Scleroderma polyrhizon).
Outer Surface: 9-13cm across when closed, 13-15cm across after opening, spherical to somewhat pear-shaped, fleshy to corky, very hard when dry; whitish to yellowish brown and finally brown; surface covered with a layer of cottony mycelium when immature, then smooth to cracked-scaly, with adherent particles of soil, at times with scales more or less defined (not as well as in S. floridanum); flesh of peridium [covering layer] colored as the surface, more than 0.5cm thick when fresh (according to Coker and Couch 1928), or 0.1-0.3cm thick dried; opening typically in star-like fashion, the spore mass being revealed and the fruitbody taking on the aspect of a Geastrum species, at a late stage of expansion the gleba is lost altogether, (Guzman), 4-12cm across, spherical to ovoid or irregular when closed, expanding up to 15.5cm to resemble a large earthstar [Geastrum] when open (splitting open when mature into 4-8 star-like rays and exposing the spore mass); outer layer "thick, hard, rind-like", "dingy white to straw-colored or pale yellow-brown", "rough, areolate to somewhat scaly", (Bessette), 4-14cm across, flattened to spherical or irregular, sometimes lobed; "white at first, then yellowish or light brownish; cottony to rough or shallow-scaly with adhering soil"; thick-walled; at maturity splits irregularly into a varying number of wide star-like rays, exposing spore mass, (McKnight), 4-10(13)cm across, peridium 0.1cm thick (Ramsey), smooth to slightly scaly, opening often star-like, in part of key with peridium > 0.1cm thick when dry, (Sims), 4-15cm across or high when closed, 12-30cm across when expanded; peridium 0.3-1cm thick, (Arora)
Spore Mass: compact to powdery; gray-brown; with whitish and yellowish filaments; when young shows alveolar structure and is surrounded by a thin cottony layer, part of the peridium, which is lost with opening of the fruitbody, (Guzman), "firm when young, becoming powdery, brown to purplish brown, becoming blackish brown at maturity", (Bessette), dark brown (McKnight, Ramsey), "at first firm and pallid, soon dark gray to purple-black or black (and still firm), eventually becoming brown to dark brown or purple-brown and powdery", (Arora)
Stem: sessile, basal region occasionally with veins or rhizoids, (Guzman), none; more than half of spore case often remains below surface, "attached by white string-like or flattened strands", (McKnight), sessile with rhizoid mass (Ramsey), often attached by mycelial "root" of tough fibers, (Arora)
Odor: none (Miller)
Taste: unknown (Miller)
Microscopic: spores (6)7.2-9.6(12) x (6)7.2-9.6(12) microns, including the spines that are difficult to specify, 0.8 microns long, slightly spiny, subreticulate, reticulation generally irregular, (western material has more reticulate spores); spores reddish brown in Melzer''s reagent, yellowish brown in KOH; in immature material is possible to observe spores that are smooth and shortly pedunculate to spiny subreticulate, with slender walls; clamp connections present, (Guzman), spores 5-10 x 5-10 microns, round, "with short spines, sometimes forming a partial reticulum, purple-brown", (Bessette), spores 6-10 x 6-10 microns, round in shape, spines project into deciduous colorless sheath from complete or incomplete reticulum, spores brown, (McKnight), spores 10-14 x 10-14 microns, in part of key with ornamentation catenulate-reticulate with wings joining the spines, (Sims)
Habitat / Range
underground when spherical, above ground when opened, gregarious in pastures, rarely in woods, (Guzman), single or in groups "on or partially buried in sandy soil, often along roads or on hillsides", August-November, (Bessette), forms underground, single to clustered, "on hard clay or sandy soil under hardwoods, in lawns, or on bare soil", late summer and fall, (McKnight), rare under deciduous trees (Ramsey), "on hillsides, along roads, in ditches, poor soil, sand, asphalt, gravel, etc.", (Arora)
Similar Species
Scleroderma texense is not known to occur in the Pacific Northwest, but is similar: differentiated by the scales on the peridium (conspicuously cracked-scaly with scales flat or subpyramidal, irregular in form, reaching more than 0.2cm in diameter and overlapping), the thickness of the walls of the peridial hyphae (more than 1 micron in the outer layer of the peridium, in S. polyrhizum thin or thick in this layer but not as conspicuous as in S. texense), and the reaction of the spore mass with KOH (yellow to reddish rose, none in S. polyrhizum), (Guzman, but a note in Sims indicates that the spores in the type material of S. texense are actually echinulate and not subreticulate, and also that the peridium of S. texense is squarrose and the spore mass distinctive fuscous black, differentiating it from Scleroderma cepa with scaly to coarsely cracked peridium and mouse-gray spore mass). Scleroderma cepa, Scleroderma laeve, and Scleroderma albidum have non-reticulate spores. Scleroderma areolatum and Scleroderma verrucosum have distinct scales, non-reticulate spores and dehiscence is rarely star-like. Scleroderma floridanum has a surface covered in irregular scales and cracks (Sims). Scleroderma citrinum has scales in rosettes and spores that often but not always have a well defined reticulum (Sims). Scleroderma bovista and Scleroderma hypogaeum have larger spores with a well defined reticulum. Scleroderma polyrhizon might be mistaken for large cup fungus such as Sarcosphaera but usually has some powdery spore mass to distinguish it, (Arora). Earthstars have an inner spore case (Arora). Mycenastrum corium has "a thick white felty outer peridium and a smooth, purple-brown inner one which splits into lobes at maturity", (Arora).
