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Scleroderma floridanum

by Michael Kuo, 6 June 2025

Found in coastal sand along the Atlantic Coast of the southeastern United States, Scleroderma floridanum looks kind of like a smaller, yellowish, beach version of Scleroderma polyrhizum; like that species it tends to break apart in a star-shaped pattern ("stellate dehiscence" in Mycologese) in old age, exposing its spore mass to wind currents.

Before breaking apart, Scleroderma floridanum features a bald, yellowish-brownish surface that develops fissures and cracks. Its surface turns brown (not red) when a drop of KOH is applied, and it often develops a twisted mass of sand and mycelium (a pseudostem) underneath its roundish fruiting body. A peek under the microscope reveals partially reticulate spores . . . but I hasten to add that this feature can be difficult to assess without a lot of rolling the fine-focus control and contrast adjustments.

Thanks to Andy Methven for documenting, collecting, and preserving Scleroderma floridanum for study; his collection is deposited in The Herbarium of Michael Kuo.

Description:

Ecology: Presumably mycorrhizal, probably with oaks; appearing in pine-oak forests; growing gregariously, year-round in subtropical areas or in summer and fall elsewhere; originally described from Florida (Guzmán 1967); primarily distributed on the Atlantic Coast of the southeastern United States but, according to Guzmán, also appearing in Michigan, California, the Bermudas, eastern Australia, England, and Macao. The illustrated and described collection is from coastal Georgia.

Fruiting Body: 2.5–4 cm across; more or less round; surface yellowish brown, bald, becoming cracked and fissured, with pale yellowish flesh showing between the cracks; skin 1–3 mm thick, white, becoming slightly pinkish when sliced; spore mass white and fleshy at first, becoming purplish black with whitish mottling and eventually powdery; with a pseudostem 2–3 cm long, composed of twisted and tangled mycelial material; when mature sometimes rupturing into a star-shape, with triangular arms bent back, subtending the powdery spore mass.

Odor: Not distinctive.

Chemical Reactions: KOH brown on surface.

Microscopic Features: Spores 8–11 µm excluding ornamentation; globose or subglobose; densely spiny with spines up to 2 µm long; partially reticulate in places; golden brown in KOH. Hyphae of the peridium 3–7 µm wide; smooth; walls less than 0.5 µm thick; hyaline to yellowish in KOH; Clamp connections not found.

REFERENCES: G. Guzmán, 1967. (Guzmán, 1970; Sims, Watling & Jeffries, 1995; .) Herb. Kuo 08192001.

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Spores

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Cite this page as:

Kuo, M. (2025, June). Scleroderma floridanum. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/scleroderma_floridanum.html