This inconspicous small corticioid wood-inhabiting fungus grows on trunks and old branches of living old growth trees of Juniperus phoenicea and Cupressus sempervirens.Yet it is only found at two sites, in a valley in Sardinia (Italy) and in Tuscany (Italy). For a short period it was observed also on in central Italy (Tuscany). Both woody plant species are common in the Mediterranean area the fungal species result to be very rare; it is often observed in association with Echinodontium ryvardenii a species red-list assessed as EN. Today A. rostrata is only known from the type collection site in Sardinia and the extinction risk is very high. Hence Arrosia rostrata is assessed as Critically Endangered (EN) with a very small population size less than 50 mature individuals
Arrosia rostrata was described in 2011 (Bernicchia, et al 2011).
This unusual small, white and soft corticoid fungus with distinctive microscopic characteristic was found various times on trunks and old branches of living Juniperus phoenicea in a valley in Sardinia (Italy). Only for a short period it was observed also on Cupressus sempervirens in central Italy (Tuscany). Even if both woody plant species are common in the mediterranean area the fungal species result to be very rare and the extinction risk is very high. Today it is only present at the type collection site in Sardinia. It can be assessed as critically endangered with a very small population size less than 50 mature individuals. Mycologists are invited to look for new findings of Arrasia rostrata!
This species was described from the Lanaittu valley on the island Sardinia, Otaly (Bernicchia et al 2011), A couple of years later it was recorded on a living but not healthy Cupressus sempervirens in the natural cupress forest Cipresseta di Sant’Agnese (Siena, Tuscany, Italy, Bernicchia et al 2015).
There are 12-14 observations in one site on two Juniperus phoenicea trees in Sardinia, and 5-6 collections were recorded at one site on one Cupressus sempervirens tree in Tuscany. The Tuscany occuence does not longer exist. This species appears preently to be limited to Juniperus and to island Sardinia (Italy), finally it was observed on C.sempervirens on the italian penisola (Tuscany), but only for a short time and than dissapared. Even if both woody plant species are common in the Mediterranean area, but seldom as old growth trees, the fungal species appears to be very rare.
Today it is only present at the type collection site, and while it has been observed in similar habitat to Echinodontium ryvardenii, surveys for this latter species rarely find A. rostrata. Being known from only two trees, currently, with each containing approximately 2 mature individuals (see Dahlberg and Mueller 2011), this means that the known population size of only 4 mature individuals. Even taking into account potential additional sites that have not been found yet of this extremely rare species, the total population size probably does not exceed 50 mature individuals.
Population Trend: Decreasing
Arrasia rostrata is an unusual small, white and soft corticioid fungus with distinctive large basidiospores developing a characteristic distal refractive rostrum, from here the name “rostrata”. The species seems to be associated to the bark of old Juniperus phoenicea and also old Cupressus sempervirens.At the site at where it was found and described, it has been observed on trunks and old branches of living old Juniperus phoenicea, often growing near to Echinodontium ryvardenii.
This species resulted to be limited to Juniperus and to Sardinia, finally years later (2014) it was observed as few small spots also on a living but not with a healthy aspect Cupressus sempervirens in central Italy (Tuscany).
Even if both woody plant species are common in the mediterranean area the fungal species result to be very rare, disappeared on Cupressus and the extinction risk is very high. The species is not easy to detect, frequently in association with Echinodontium ryvardenii much easier ti observe, and the most remarkable feature are its large, beaked basidiospores, so hopefully it is growing somewhere else and has not been detected. Anyway old growth trees of Juniper and Cupressus are rare, often crash down or are harvested and used by people and need protection itshelf. These are frequently cut for many purposes such as firewood and for making items such as fireplaces and sheepfolds.
Protect old growth Juniper and Cupressus communities.
An accurate search is needed to clarify the distribution in the Med. region and old growth forests or trees of Juniper and Cupressus where hopefully the species is still present.
BERNICCHIA A., GORJON S.P., NAKASONE K.K., 2011: Arrasia rostrata (Basidiomycetes), a new corticioid genus and species from Italy. Mycotaxon 118: 257-264.
BERNICCHIA A., FACCHINI M., GORJON S.P., 2015: A new collecting area for Arrasia rostrata in Italy. Micol. Veget. Medit., 30 (1): 57-64. 2015.