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Echinodontium ballouii (Banker) H.L. Gross

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Scientific name
Echinodontium ballouii
(Banker) H.L. Gross
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
Ainsworth, A.M.
Dahlberg, A.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/71567420/71567447


A conspicuous and distinctive wood-inhabiting tooth fungus with a global distribution entirely dependent on the restricted range of Chamaecyparis thyoides, a swamp-inhabiting conifer found along the coast of the eastern USA. Fruiting (reproduction) requires very old trees and, following some dedicated survey work, only ca. 20 occupied trees (estimated to comprise 40 ramets) are thought to exist. Although good estimates exist for the past decline of its associated tree in certain US states due to logging, this is not the case over its entire range. Furthermore this decline largely ceased with the declining need for shipbuilding timber. Therefore only Criterion D is appropriate. Allowing for the existence of as yet unrecorded occupied trees, this species is considered to have a small population of less than 250 individuals and is assessed globally as Endangered.

Taxonomic notes

Described by Banker (1909) who, presciently doubting if this and Echinodontium tinctorium (generic type) were congeneric, assigned it to Steccherinum. It was recombined in Echinodontium by Gross (1964). However, DNA sequence data generated by Binder (reported in Shernoff 2007a) indicated that E. ballouii is closely related to E. ryvardenii. This, in turn, has been shown to be relatively distantly related to the type of the genus (Larsson & Larsson 2003) and so both species will require a new generic name in due course. However this has no bearing on the conservation status of these fungi.

Geographic range

Restricted to the range of Chamaecyparis thyoides Atlantic white cedar (although not a true cedar) along the east coast of the USA. This conifer occurs in a narrow belt (usually within 150 miles of the coast) from Maine to Georgia on the Atlantic coast and from Florida to Mississippi on the Gulf of Mexico coast. There are two disjunct populations of the conifer which have been recognised as distinct taxa at specific or infraspecific rank. 

In the fruiting state, this fungus is further restricted to the oldest stands of the tree and has, thus far, only been recorded in the northernmost (Atlantic coastal) population/taxon of C. thyoides. The included map shows the potential distribution of E. ballouii by showing the distribution of C. thyoides.

Population and Trends

Three specimens collected in 1908 and 1909 by Ballou from the type locality: New Jersey, Ocean Co., Forked River and described by Banker (1909). Gross (1964) remarked that he had made several unsuccessful attempts to refind the fungus. Gilbertson and Ryvarden (1986) noted no further collections had been made and that it was possibly extinct. It was rediscovered by Lawrence Millman and William Neill in March 2006 at a Nature Conservancy site in Hillsborough County, New Hampshire, in three discrete areas several hundreds of metres apart, within ca. 150 hectares of surveyed swamp (L. Millman in litt). In late February/early March 2015, L. Millman (reported in email of 03 Mar 2015 to A.M. Ainsworth) “snowshoed extensively around the New Jersey Pine Barrens (three different locales) and discovered no fruitings of Echinodontium ballouii as well as no truly old Atlantic white cedars”. The objective of this search was to revisit sites not far from where the type specimen was discovered by Ballou in Ocean Co. NJ although Millman (pers.comm.) notes that “since that area has been extensively logged in the last hundred years, it’s unlikely that I’ll find new specimens”. Furthermore Millman goes on to say “I’ve investigated virtually all of the Atlantic White Cedar swamps in the Northeast, including one on Naushon Island, MA, which has some singularly old trees, and I’ve not found any evidence that E. ballouii exists beyond the single New Hampshire site”. Current number of known occupied trees 15-20 (Millman in litt.). 

Trends are probably best expressed in trends for its tree associate. Fide Shernoff (2007b), C. thyoides “was on the verge of extinction a hundred years ago” due to cutting for timber. Its extinction was considered “likely within a decade”. More recently however its timber has fallen out of favour and it has been re-established along the Atlantic coast. However on visiting one such site, Millman and Neill soon gave up the search as the swamp did not contain any suitable old growth (reported in Shernoff (2007b). Burke and Sheridan (2005) describe the tree as “globally threatened and coastally restricted”. New Jersey’s C. thyoides population has decreased 74% from its estimated historic area (from 47,000 ha down to 12,100 ha) (New Jersey Department of Environmental Protection 2003). Chamaecyparis thyoides is assessed as Least Concern (IUCN 2013) with the motivation "Exploitation in the past has impacted this species primarily in terms of numbers of mature trees, but this situation has reversed in most places and the species is likely to recover. It has a very wide range and is present in most of its swamp forest habitat, including within many reserves".

Population Trend: unknown

Habitat and Ecology

This species fruits on older trees (ca. 100 y fide Millman in Shernoff 2007) from positions consistent with being a heartrotter although it can also fruit on dead attached thin branches consistent with the mycelium spreading outwards from the trunk’s inner core. Chamaecyparis thyoides favours swampy sites hence the fungus is best surveyed early in the year when the ground is frozen.


Today’s acreage of C. thyoides is “only a small fraction of the original” largely due to logging, wildfires and drainage of peatlands for agriculture (Derby and Hinesley 2005 and refs therein). Millman (in litt.) states that the site he and Neill discovered is a Nature Conservancy site and thus preserved.

Conservation Actions

Site protection is required for all the remaining populations of this fungus. 
Younger C. thyoides trees should be allowed to reach old age and die in situ to maximise the likelihood that E. ballouii will persist as an extant species and colonise new sites or recolonise its former sites.

Source and Citation

Ainsworth, A.M. 2019. Echinodontium ballouii. The IUCN Red List of Threatened Species 2019: e.T71567420A71567447. https://dx.doi.org/10.2305/IUCN.UK.2019-1.RLTS.T71567420A71567447.en .Accessed on 5 February 2024

Country occurrence