Vascellum F. Šmarda, in Pilát, Fl. ČSR, B-1, Gasteromycetes: 760. 1958.
Type: Vascellum depressum (Bonord.) F. Šmarda, Bull. int. Acad. pol. Sci. Lett. 1: 305. 1958.
Vascellum was erected as a genus by F. Šmarda in 1958, published in Pilát, Fl. ČSR, B-1, Gasteromycetes. Kreisel (1993) writes that the foundation of this genus is based on a thin wall of differentiated tissue, called the diaphragm, which divides the gleba and the subgleba. Species placed within this genus typically have an abundance of paracapillitium tissue, and often a low abundance of eucapillitium tissue. Since Šmarda’s genus was established, many workers have added to Vascellum: Kreisel (1962, 1963, 1993), Ponce de Leon (1970), Smith (1974), and Demoulin (1975). However, with the advent of molecular systematics, works by Larsson and Jeppson (2008) and Bates (2004) have shown that Vascellum is a polyphyletic group, with many species belonging in the Lycoperdon clade. Names, such as Vascellum pratense, have since been officially transferred to Lycoperdon. The genus is still problematic, since the type species, Vascellum depressum Bonard., has been accepted as a synonym of Lycoperdon pratense Pers. (Jeppson 2011), and many species have yet to be sequenced and systematically analyzed. All other species once included in Vascellum need to go elsewhere, ending up in Lycoperdon or some other recognized genus, or a new genus depending on their phylogenetic relationships. Until all species in the Vascellum genus have been phylogenetically treated, the circumscription of Vascellum will remain questionable.
The genus currently has seventeen species that have been recorded in Index Fungorum, twenty-five including all varieties. There is currently one species historically recognized as Vascellum reported in California, Vascellum lloydianum, which is recognized as Lycoperdon lloydianum (A.H. Smith) Jarvis comb. prov. here.
Comments on Lycoperdn pratense: The diaphragm-forming Lycoperdon puffballs have similar features and it may be difficult to tell them apart. A good microscope with oil emersion capability at high power is necessary for identifying eucapillitium versus paracapillitium from various parts of the gleba. Lycoperdon pratense and Lycoperdon lloydianum are very similar in outward appearance, which can cause confusion and misidentification among them. Lycoperdon pratense has non-poroid eucapillitium, which is scarce to absent. Ponce de Leon (1970) argues that the eucapillitium in Lycoperdon pratense is absent, however it can be found along the periphery of the endoperidium wall in collections from California. Staining with LpCB or methylene blue chloride is helpful in this process, as well as having young to mid-mature fruitbodies that are fresh. Lycoperdon pratense has a wide and very well-developed diaphragm that can be seen earlier in development than that of other diaphragm-forming puffballs. One main distinction that sets Lycoperdon pratense apart from Lycoperdon lloydianum is the unique feature of eucapillitium growing out from the inner endoperidium walls into the gleba, whereas the eucapillitium grows strictly out from the inner diaphragm wall in L. lloydianum. Both of these grassland species have been collected together in the same habitat. However, Lycoperdon pratense is a rare species in California. Lycoperdon curtisii is smaller (under 20 mm broad), has Lycoperdon-type eucapillitium that can be found along the periphery of the inner endoperidium wall, a reduced subgleba, and smaller echinulate spores. The type for the genus Vascellum, V. depressum (Bonord.) F. Šmarda, has been accepted as a synonym of Lycoperdon pratense Pers. (Larsson 2008), and this is supported with the ITS analysis. The ML tree produced in this analysis shows Vascellum species (now in Lycoperdon) as a monophyletic clade within the Lycoperdon clade, with 92% bootstrap and 100% PP. Despite the similarities in outward appearance of Lycoperdon pratense and Lycoperdon lloydianum, the ITS sequence data suggests that these are two separate species with strong bootstrap and PP support within the Vascellum clade of Lycoperdon.
reference: Larsson, E., & Jeppson, M. (2008). Phylogenetic relationships among species and genera of Lycoperdaceae based on ITS and LSU sequence data from north European taxa. Mycological Research, 112(1), 4-22.
Vascellum depressum (Bonord.) F. Šmarda, Bull. int. Acad. pol. Sci. Lett. 1: 305 (1958)
Vascellum pratense (Pers.) Kreisel, Feddes Repert. 64: 159 (1962)