Entoloma hochstetteri
Entoloma hochstetteri, also known as the blue pinkgill, sky-blue mushroom or similar names, is a species of mushroom that is native to New Zealand. The small mushroom is a distinctive all-blue colour, while the gills have a slight reddish tint from the spores. The blue colouring of the fruit body is due to three azulene pigments. Whether "Entoloma hochstetteri" is poisonous or not is unknown. The Māori name for the mushroom is werewere-kokako, because its colour is similar to the blue wattle of the kōkako bird. This species was one of six native fungi featured  in a set of fungal stamps issued in New Zealand in 2002. It is also featured on the New Zealand fifty-dollar note. With "E. hochstetteri"'s inclusion, this makes it the only banknote in the world which features a mushroom on it. In a 2018 poll, "E. hochstetteri" was ranked first by Manaaki Whenua – Landcare Research for its pick as New Zealand's national fungus. Taxonomy. The species was first described as "Cortinarius hochstetteri" in 1866 by the Austrian mycologist Erwin Reichardt, before being given its current binomial in 1962 by Greta Stevenson. It is named after the German -Austrian naturalist Ferdinand von Hochstetter. In 1976 Egon Horak combined "Entoloma hochstetteri" and "Entoloma aeruginosum" from Japan with "Entoloma virescens", first described from the Bonin Islands in Japan. In 1989 S. Dhancholia recorded "E. hochstetteri" in India. In 1990 Tsuguo Hongo from Japan examined "E. hochstetteri" and "E. aeruginosum" and concluded that they were different taxa, because of difference in the size of the spores and the shape of the pseudocystidia. In 2008 Horak recognized "E. hochstetteri" as a different species from "E. virescens", while noting that "it is open to speculation" whether taxa such as "E. virescens" are the  same species. A similar mushroom is found in Australia and mycologists differ as to whether it is "E. hochstetteri", "E. virescens" or a separate species. Description. "Entoloma hochstetteri" has a small delicate epigeous (above-ground) fruit body (basidiocarp). The cap may be up to 4 cm (1.4 in) in diameter and conical in shape. The cap colour is indigo-blue with a green tint, and is fibrillose. The cap margin is striate and rolled inwards. The gill attachment is adnexed or emarginate, gills are thin and 3–5 mm wide, essentially the same colour as the cap, sometimes with a yellow  tint. The cylindrical stipe (stalk) is up to 5 cm (2 in) long by 0.5 cm thick, fibrillose and stuffed. The spore print is reddish-pink. The spores are 9.9–13.2 by 11.8–13.2 μm, tetrahedric in shape, hyaline, smooth and thin-walled. The basidia are 35.2–44.2 by 8.8–13.2 µm, club-shaped, hyaline, and with two or four sterigmata. Mythology. The Ngāi Tūhoe describe that the Kōkako bird ("Callaeas wilsoni") got its blue wattles from it rubbing its cheek against the mushroom. Thus giving the mushroom the title of "werewere-kokako". Habitat and distribution. "Entoloma hochstetteri" is common in forests throughout New  Zealand, where it grows on soil among litter in broadleaf/podocarp forest. It fruits in January to July. It was also reported from India in 1989 and from Australia, though it is unclear whether these are the same species or whether "E. hochstetteri" is endemic to New Zealand. Toxicity. Although many members of the genus "Entoloma" are poisonous, the toxicity of this species is unknown. It has been investigated to see if its blue colouring might be manufactured as a food dye.