Laccaria oblongospora has only been reported from established Pinus palustris (Longleaf Pine) stands along the United states Gulf Coast into Florida, but it may occur throughout P. paulustris’ range. Based on Mycoportal, GBIF, and iNaturalist records, the species has only been observed three times since the species was published in 1984. The known current population size is around 70 and that it has rarely been reported over the past 40 years, but taking into account potential additional sites the total population size is estimated to be between 7,000 and 14,000 mature individuals distributed in isolated subpopulations along the Gulf Coast into Florida and potentially up the Atlantic coast following the distribution of its mycorrhizal partner, P. palustris. While there are ongoing conservation efforts aimed at P. palustris recovery and threat mitigation, the appropriate habitat for L. oblongospora has been drastically reduced over the past three generations, 50 years. Longleaf Pine forest area has been by reduced by 80-90% over the past 100+ years. The area of appropriate habitat for L. oblongospora declined over the past three generations from approximately 7.5 million ha in 1975 to 1.8 million ha in 2020, a reduction of around 77%. Additionally, it is unknown how L. oblongospora has responded to the replanting initiatives as the original collections were from well-established stands. As L. oblogospora grows in obligate association with P. palustris, it is suspected that its population has declined by approximately 75%. It is assessed as Endangered.

Laccaria oblongospora is restricted to Pinus palustris (Longleaf Pine) stands of the USA. It has only been reported from the Gulf Coast and Florida, but it may occur throughout P. paulustris’ range. All but three reports of this species were collected in Mississippi or eastern Texas. The three Florida observations are from the panhandle and near Gainesville. Based on Mycoportal, GBIF, and iNaturalist records, these are the only three observations since the species was published in 1984. It is possible that some of the observations in iNaturalist identified as L. proxima are L. oblongospora, but even if that is the case, the species has rarely been encountered.

Laccaria oblongospora has only been reported from Pinus palustris (Longleaf Pine) stands, and has rarely been encountered. Given that the known current population size is around 70 and that it has rarely been reported over the past 40 years, extrapolating to include additional sites throughout its potential range, the total population size is estimated to be between 7,000 and 14,000, distributed in isolated subpopulations along the Gulf Coast into Florida and potentially up the Atlantic coast following the distribution of its mycorrhizal partner, P. palustris.

P. palustris is assessed as Endangered on the IUCN Red List (Farjon 2013), but that assessment needs to be updated. NatureServe (2024) lists it as G5, or not under extinction risk. The difference in rankings is that extensive conservation efforts, including replanting initiatives, have been undertaken since the IUCN assessment was published in 2013. However, even with the conservation / replanting efforts the appropriate habitat for L. oblongospora has been drastically reduced over the past three generations, 50 years. Longleaf Pine forest area has been by reduced by 80-90% over the past 100+ years. While recent conservation efforts have increased its area and number of trees, Longleaf Pine forests / plantations now cover only 1.8 million ha (NatureServe 2024), reduced from 12 million ha in 1950 (Gilliam and Platt 2006). Thus, the area of appropriate habitat for L. oblongospora declined over the past three generations from approximately 7.5 million ha in 1975 to 1.8 million ha in 2020, a reduction of around 77% (Gilliam and Platt 2006, Fig. 1). Additionally, it is unknown how L. oblongospora has responded to the replanting initiatives as the original collections were from well-established stands. As L. oblogospora grows in obligate association with P. palustris, it is suspected that its population has declined by approximately 75% over the past three generations.

The species has only been reported in association with Pinus palustris (Longleaf Pine) in very sandy soil along the United States Gulf Coast into Florida. Known records are from established stands of P. palustris and it is not known how the species is responding to P. palustris replanting efforts.

The quality of habitat was greatly reduced due to loss of its mycorrhizal partner, Pinus palustris. Logging, urban development, fire suppression and encroachment of other vegetation including other species of pines and shrubs led to a decrease in 80% in P. palustris habitat (NatureServe 2024). Conservation efforts focused on mitigating these threats are ongoing and P. palustris is in recovery although the threats persist. Laccaria oblongospora has only been reported from established P. palustris stands, so while conservation efforts focused on restoring habitat are exceedingly important, it is unknown how the population of L. oblongospora is responding.

Ongoing conservation initiatives to restore Pinus palustris stands and mitigate threats to Laccaria oblongospora habitat need to continue. Survey efforts to document the distribution and abundance of the L. oblongospora are needed.