honeycomb coral slime mold - Species Profile
Conservation • Description • Habitat • Ecology • Distribution • Taxonomy
Conservation Status
IUCN Red List
not listed
NatureServe
not listed
Minnesota
not listed
Description
Protostelid slime molds are relatively unknown and easily overlooked. They were first recognized in the early 1960s and have been little studied since. There are 36 currently accepted species, and possibly twice that number of undescribed species. Most are microscopic. Only a few are visible to the naked eye.
Honeycomb coral slime mold occurs in Europe, Asia, and North America. In the United States it occurs east of the Great Plains and on the West Coast, and there are scattered populations around major metropolitan areas between. It occurs across across southern Canada and north in the west into Alaska. It is found on shaded rotting wood of fallen logs and branches, in open, wet to moderately moist deciduous, coniferous, and mixed forests. It does not feed on the wood but on bacteria associated with the rotting wood. It can form extensive colonies one meter or more long. It is very short lived, appearing after a soaking rain and disintegrating in just a few days.
Honeycomb coral slime mold first appears as a thin, watery, translucent, mucus-like layer of protoplasm (plasmodium). It creeps across the substrate, engulfing bacteria, protozoa, and particles of nonliving organic matter. Eventually, the plasmodium fruits, converting to spore-bearing structures (sporocarps). The conversion takes about six hours.
The sporocarps are erect, slender, translucent columns appearing in densely compacted clusters forming a honeycomb-like mound up to 4″ or more in diameter. The columns are 1 ⁄32″ to ⅜″ (1 to 10 mm) long, 1 ⁄64″ to 3 ⁄64″ (0.5 to 1.0 mm) in diameter, and tapered. When they first appear they are slimy, translucent, and usually white, rarely pink or yellow. Later, they have a frosted or powdery appearance due to a dense covering of tiny, white, spores on long, thread-like stalks. The spores may actually be one-celled sporangia.
It is not edible.
Similar Species
Habitat and Hosts
Open, wet to moderately moist, deciduous, coniferous, and mixed forests
Ecology
Season
June through October
Distribution
Sources
Ceratiomyxa porioides (Alb. & Schwein.) J.Schröt., 1889 in Bánki, O., Roskov, Y., Döring, M., Ower, G., Hernández Robles, D. R., Plata Corredor, C. A., Stjernegaard Jeppesen, T., Örn, A., Pape, T., Hobern, D., Garnett, S., Little, H., DeWalt, R. E., Miller, J., Orrell, T., Aalbu, R., Abbott, J., Abreu, C., Acero P, A., et al. (2026). Catalogue of Life (2026-06-19 XR). Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgy8b
Mycology Collections Portal (MyCoPortal) https://www.mycoportal.org/portal/collections/index.php). Accessed 7/20/2026.
Occurrence
Common
Taxonomy
Kingdom
Protozoa (Protozoans)
Phylum
Amoebozoa
Subphylum
Mycetozoa (Slime Molds)
Class
Protosteliomycetes
Subclass
Incertae sedis
Order
Protosteliales
Family
Ceratiomyxaceae
Genus
Ceratiomyxa (Coral Slimes)
Species
Historically, Ceratiomyxa porioides was considered a variety of Ceratiomyxa fruticulosa. Though strikingly different in appearance, the morphology alone was not considered sufficient to separate them as distinct species.
A recent molecular phylogenetic analysis (Fry, N. W. et al., 2024) found “molecular evidence that fruiting body morphology does correspond to species level diversity.” The authors formally raised Ceratiomyxa porioides to species level.
Subordinate Taxa
Synonyms
Ceratiomyxa fruticulosa var. porioides
Ceratiomyxa mucida var. porioides
Ceratium porioides
Ceratium porioides var. flavum
Ceratium porioides var. lacteum
Craterium porioides
Famintzinia porioides
Common Names
honeycomb coral slime mold
