Ceratiomyxa fruticulosa (coral slime mold)

Coral slime mold, Ceratiomyxa fruticulosa, is a fairly common sight in the Midwest, especially after heavy rains. Look for spreading white patches on the well-decayed, barkless deadwood of hardwoods or conifers—then, look closely at the tiny, coral-like structures that make up the patches of white: individual translucent tubes, sometimes branched once or twice, under a centimeter high.

There are two other species of Ceratiomyxa, both tropical and therefore unlikely to be found in the Midwest. Ceratiomyxa sphaerosperma looks like tiny little clusters of Ceratiomyxa fruticulosa, set atop tiny stems of transparent jelly–and Ceratiomyxa morchella looks like a tiny white morel mushroom with a transparent stem.

Range of Fuligo septica

midwestern range

Ceratiomyxa fruticulosa
coral slime mold spreads across logs in large patches

Ceratiomyxa fruticulosa
the wood is usually well-decayed, without its bark


Ceratiomyxa fruticulosa
fresh specimens look like corals

Ceratiomyxa fruticulosa

Ceratiomyxa fruticulosa
in close-up coral slime is composed of tiny translucent columns

Ceratiomyxa fruticulosa
this form of coral slime almost appears like a fungus with pores, and is designated as a "poroid form" by slime mold scientists—or, sometimes, as a separate species, Ceratiomyxa poroides

References: Farr 1981, Stephenson & Stempen 2000, Nibblet 2017, Ing 2020.

Kuo, Michael & Melissa Kuo (November, 2021). Ceratiomyxa fruticulosa (coral slime mold). Retrieved from the midwestnaturalist.com website: www.midwestnaturalist.com/ceratiomyxa_fruticulosa.html

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