Sarcosphaera

Sarcosphaera is a fungal genus within the Pezizaceae family. It is a monotypic genus, containing the single species Sarcosphaera coronaria, commonly known as the pink crown, the violet crown-cup, or the violet star cup. It is a whitish or grayish cup fungus, distinguished by the manner in which the cup splits into lobes from the top downward. It is commonly found in the mountains in coniferous woods under humus on the forest floor, and often appears after the snow melts in late spring and early summer. The fungus is widespread, and has been collected in Europe, Israel and the Asian part of Turkey, North Africa, and North America. In Europe, it is considered a threatened species in 14 countries. Although several taxa have been described as Sarcosphaera species since the introduction of the genus in 1869, most lack modern descriptions, have been transferred to the related genus Peziza, or are considered synonymous with S. coronaria. The fruit body, typically found partially buried in soil, is initially like a fleshy hollow ball, and may be mistaken for a puffball. Unlike the latter, it splits open from the top downwards to form a cup with five to ten pointed rays, reaching up to 12 cm (4.7 in) in diameter. It is lavender-brown on the inside surface, and whitish outside, but usually dingy from adhering soil. Characteristic microscopic features include asci that are amyloid (so their tips stain blue at the tip with iodine), and smooth, blunt-ended, ellipsoid spores with large oil droplets. Sarcosphaera coronaria—once thought to be a good edible—is not recommended for consumption, after several reports of poisonings causing stomach aches, and in one instance, death. The fruit bodies are known to bioaccumulate the toxic metalloid arsenic from the soil. The genus was first described by Bernhard Auerswald in 1869, to accommodate the species then known as Peziza macrocalyx. Sarcosphaera coronaria was originally named Peziza coronaria by the Dutch scientist Nikolaus Joseph von Jacquin in 1778, and underwent several name changes before being assigned its current name in 1908 by Joseph Schröter. The Greek genus name means 'flesh ball'; the Latin specific epithet, coronaria, refers to the crown-like form of the open fruit body. The species is commonly known by various names, including the 'crown fungus', the 'pink crown', the 'violet crown-cup', or the 'violet star cup'. Several taxa have been named as belonging to the genus Sarcosphaera over the years, but most lack modern descriptions and have not been reported since their original collections. For example, Sarcosphaera funerata was renamed by Fred Jay Seaver in 1930 based on the basionym Peziza funerata, originally described by Cooke in 1878. Sarcosphaera gigantea was a species collected from Michigan, originally described as Pustularia gigantea by Heinrich Rehm in 1905, and considered distinct from S. coronaria on the basis of its smaller spore size. Sarcosphaera ulbrichiana was described by Wilhem Kirschstein in 1943. Other taxa have been reduced to synonymy with S. coronaria, or transferred to other genera. Sarcosphaera eximia (originally Peziza eximia Durieu & Lév. 1848, and later transferred to Sarcosphaera by René Maire), Sarcosphaera crassa (considered by Zdeněk Pouzar in a 1972 publication to be the correct name for S. coronaria) and Sarcosphaera dargelasii (originally Peziza dargelasii Gachet 1829, transferred to Sarcosphaera by Nannfeldt) are now considered synonyms of S. coronaria. Sarcosphaera ammophila (originally Peziza ammophila Durieu & Mont.) and Sarcosphaera amplissima (originally Peziza amplissima Fr. 1849) have since been transferred back to Peziza. The 10th edition of the Dictionary of the Fungi (2008) considers Sarcosphaera to be monotypic, and Index Fungorum has only Sarcosphaera coronaria confirmed as valid. In 1947, Helen Gilkey described the genus Caulocarpa based on a single collection made in Wallowa County, Oregon. The type species, C. montana, was thought to be a truffle (formerly classified in the now-defunct Tuberales order) because of its chambered fruit body and subterranean growth habit. It was later noted by mycologist James Trappe to strongly resemble Sarcosphaera. Thirty years later, Trappe revisited the original collection site in eastern Oregon and found fresh specimens that closely matched Gilkey's original description. Some specimens, however, had opened up similar to Sarcosphaera, suggesting that the original specimens had 'simply not emerged and often not opened due to habitat factors.' Microscopic examination of the preserved type material revealed the species to be Sarcosphaera coronaria (then called S. crassa), and Caulocarpa is now considered a generic synonym of Sarcosphaera. Sarcosphaera is classified in the family Pezizaceae of the order Pezizales. Phylogenetic analysis of ribosomal DNA sequences suggests that Sarcosphaera forms a clade with the genera Boudiera and Iodophanus, and that the three taxa are a sister group to Ascobolus and Saccobolus (both in the family Ascobolaceae). Species in the families Pezizaceae and Ascobolaceae are distinct from other Pezizalean taxa in the positive iodine reaction of the ascus wall. In a more recent (2005) phylogenetic analysis combining the data derived from three genes (the large subunit ribosomal rRNA (LSU), RNA polymerase II (RPB2), and beta-tubulin), Sarcosphaera was shown to be closely related to the truffle genus Hydnotryopsis, corroborating earlier results that used only the LSU rDNA sequences. Sarcosphaera is partly hypogeous (fruiting underground) and emerges from the ground as a whitish to cream-colored hollow ball. Young specimens are covered entirely by an easily removed thin protective membrane. As it matures, it splits open to expose the inner spore-bearing layer (hymenium). The cup is up to 12 cm (4.7 in) in diameter, roughly spherical initially but breaking up into a series of five to ten raylike projections, which give the fruit body the shape of a crown. The outer surface of the cup is white, while the inner surface is lilac-gray, although in age the color may fade to a brownish-lavender color. The flesh is white, thick, and fragile. Some specimens may have a short, stubby stalk. The spores are hyaline (translucent), smooth, and ellipsoid with the ends truncate. They have dimensions of 11.5–20 by 5–9 µm, and usually contain two large oil drops. The paraphyses (sterile, filamentous cells interspersed among the asci, or spore-producing cells) are 5–8 µm wide at the tip, branched, septate (with partitions that divide the cells into compartments), and constricted at the septa. The asci are cylindrical, and measure 300–360 by 10–13 µm; the tips of the asci stain blue with Melzer's reagent. The finely cylindrical paraphyses have slightly swollen tips and are forked at the base.