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Geastrum morganii

[ Basidiomycota > Geastrales > Geastraceae > Geastrum . . . ]

by Michael Kuo

This rare earthstar is similar in appearance to the much more common Geastrum saccatum; like that species it is fairly small and features a spore case that appears to be nested comfortably in a small bowl. However, Geastrum morganii has a prominent, irregularly grooved beak, arms that bruise slowly pinkish, and a distinctive reddish to reddish brown coating on the outer surface of young specimens.

In North America Geastrum morganii is apparently limited to the Midwest—but its documentation is uneven, and it is not often described; it may have been recorded elsewhere as "Geastrum saccatum" or another species.

Thanks to Susan Kritzberg for documenting, collecting, and preserving Geastrum morganii for study; her collection is deposited in The Herbarium of Michael Kuo.

Description:

Ecology: Saprobic; growing alone or gregariously under hardwoods; often found near rotting stumps; summer and fall; originally described from the United States (Lloyd 1901, unspecified location); in North America fairly widely distributed east of the Great Plains, especially in the Midwest; also known from Central America, South America, Europe (coastal France and Spain, where it is very rare), and Oceania.

Immature Fruiting Body: An onion-shaped ball 1.5–2.5 cm wide and up to 3 cm high, with a reddish to reddish brown covering that sometimes separates in places to reveal a paler surface underneath.

Mature Fruiting Body: 3–4 cm across; with 5–7 recurved, more or less triangular arms underneath a ball-shaped spore case 1.5–3 cm across; outer surface of arms with a reddish brown covering; inner (upper) surface of arms beige, bruising pink to reddish, bald but developing cracks and fissures (sometimes cracking deeply and uniformly to create a small saucer like that of Geastrum triplex); spore case more or less round, smooth or faintly felty, with a papery skin, brown to brownish, with an irregularly grooved (or at least wrinkled) conical beak; interior of spore case initially solid and white but soon powdery and dark brown; base attached to white rhizomorphs.

Microscopic Features: Spores 2.5–4 µm including ornamentation of low, dense spines under 0.5 µm; long; globose; yellowish to brownish or brown in KOH. Capillitial threads 3–6 µm wide; aseptate; walls smooth or roughened, 1–2 µm thick; brownish-walled in KOH.


REFERENCES: Lloyd, 1901. (Coker & Couch, 1928; Smith, 1951; Ponce de Leon, 1968; Smith, Smith & Weber, 1981; Hernández Caffot et al., 2013; Jeppson et al., 2013; de Oliveira Sousa et al., 2014; Zamora et al., 2014.) Herb. Kuo 08182101.


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Geastrum morganii

Geastrum morganii

Geastrum morganii

Geastrum morganii

Geastrum morganii

Geastrum morganii

Geastrum morganii

Geastrum morganii
Spores



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Cite this page as:

Kuo, M. (2021, August). Geastrum morganii. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/geastrum_morganii.html