Given the estimated population size and extent and area of occurrence, this taxon exceeds the limit value for red-listing. Additionally, populations appear to be stable across west and eastern parts of Canada, Norway and Finland even with suspected declines in Sweden and other parts of Europe and the US.

Alloclavaria purpurea (Fr.) B.T. Dentinger & D.J. McLaughlin has been separated into a new genus, as the type, based on phylogenetic and morphological evidence from 2006. Alloclavaria, or ‘‘the other Clavaria,’’ refers to the morphologically similar genus and basionym of the type species Clavaria purpurea (Fries).

A. purpurea is a coral-like, club fungus with approximately 10–12 cm high, unbranched spindles which usually grow tufted and often in large numbers. The spindles are very fragile, cylindrical or flattened with a longitudinal central groove. They are ±hollow and can be twisted and pointed at the top. The coloration is first grey-violet and then later light grey-brown as it matures. The spindle surface can be slightly wrinkled and a defining feature is that it has hymenial cystidia, which distinguishes it from Clavaria. It is possible that A. purpurea remains a species complex and there may be additional species included in the genus (e.g., Clavaria indica and C. nebulosoides). The purple coral fungus Clavaria zollingeri Lév. (1846) is vaguely similar but moderately branched.

Alloclavaria purpura remains as the only species in the genus. There is limited knowledge of its ecology, but appears to be most commonly found in northern and/or alpine ecosystems. It is not a Mediterranean taxa, but being assessed during this initiative.

Alloclavaria purpurea has been mainly found in temperate and boreal forests in northern latitudes and alpine ecosystems, typically in moist and mineral rich coniferous forests. In North America, populations appear to be concentrated on the West coast, Rocky Mountains, around the Great Lakes region and additionally on the East coast. No reproducing or mature individuals have been detected in Central America, although one recod from DNA metabarcoding in a broadleaf forest of Panamá has been observed. In South America, an interesting record from a cloud forest in Perú has not been verified with DNA or microscopy, although macromorphologically similar. In Europe, observations appear to be concentrated in northern regions such as Scandanavia and Russia with endangered or extirpated populations to the south in central Europe. A. purpurea also occurs in Japan and China, but these records need to be checked more thoroughly.

Given the estimated population size and the widespread occurrence, this taxon exceeds the limit value for red-listing; however, the estimated decline varies across regions. Stable populations in Finland and Norway suggest that this species is not threatened while declining suitable habitat in Sweden over the last 50 years indicates otherwise. In North America, populations appear to be stable in the northeast, but interior regions, such as on the east side of the Canadian Rockies, may be vulnerable. Earlier records in more southern, temperate regions and probably extirpation suggest that this species could be prone to changes in climate and land use change.

Alloclavaria purpurea is widespread and most commonly found in boreal forest soils. It is particularly fond of humid spruce forests with mineral-rich soils. Sometimes it has been found in grassy forest glades and more frequently in moist moss mats. It can be found in oversilted spruce swamp forests and at the bottom of ravines or canyon valleys. The species is significantly favored by lime and associated with nutrient-rich coniferous forests with herbaceous groundcover. Collections of basidiomes appear only in a few places in each site. Each site probably contains one or a few genetically unique fungal individuals (genets) that can all be fragmented into several free-living but genetically identical mycelia (ramets, corresponding to the IUCN definition of individual). The purple spindles are short-lived, but the soil mycelium can be long-lived, several decades, or more. Global DNA metabarcoding initiatives have found DNA occuring almost occuring exclusively in forest organic and mineral soil horizons extending from Canada and the US to Panama, Estonia, Russia and China, although there are occurences in grasslands (<5%). There has been disagreement in the literature about the ecology of A. purpurea. It has been understood to be a decomposer in the past, but the fungus appears to be associated with trees and/or moss and it likely forms mycorrhiza based on isotopic analysis of basidiomes (Krokonin et al., 2018). This has not been anatomically investigated in resynthesis experiments or with isotopic labelling. We assume a generation time of 50 years following its probable biotrophic status.

Alloclavaria purpurea requires forest environments with constant very high humidity. It cannot withstand a clear-cut or disturbances that affect the hydrology of the site. It is possible that climate induced drought or wildfires may have an impact on populations in the long-term. The effect of nitrogen deposition is unclear.