Bovista

Bovista is a genus of fungi commonly known as the true puffballs. It was formerly classified within the now-obsolete order Lycoperdales, which, following a restructuring of fungal taxonomy brought about by molecular phylogeny, has been split; the species of "Bovista" are now placed in the family Agaricaceae of the order Agaricales. "Bovista" species have a collectively widespread distribution, and are found largely in temperate regions of the world. Various species have historically been used in homeopathic preparations.
Description.
Fruit bodies are oval to spherical to pear-shaped, and typically in diameter with a white or light-colored thin and fragile exoperidum (outer layer of the peridium). Depending on the species, the exoperidium in a young specimen may be smooth, granular, or finely echinulate. This exoperidium sloughs off at maturity to expose a smooth endoperidium with a single apical pore (ostiole). The fruit bodies may be attached to the ground by fine rhizomorphs that may appear like a small cord. Some species develop a subgleba—a sterile base that is typically not well developed. The fruit bodies of mature specimens can develop surface alterations such as scales, plates, areolae, or verrucae. At the microscopic level, these features are made of hyphae, sphaerocysts (rounded cells), claviform (club-shaped) cells. "Bovista sclerocystis" is the only species in the genus with mycosclereids (setoid elements) in the peridium.
Spores are brown to purple-brown, roughly spherical or ellipsoid in shape, and 3.5–7 μm in diameter. A short or long pedicel (stalk) may be present. At maturity, the entire fruit body may become detached from the ground, and the spores spread as the puffball is blown around like a tumbleweed.
In "Bovista", the capillitium (a network of thread-like cells in which the spores are embedded) is not connected directly to the interior wall of the peridium. Instead, it is made of separate, irregularly branched units that end in tapered points. This type of capillitium, also present in the puffball genera "Calbovista" and "Bovistella", has been called the ""Bovista" type by Hanns Kreisel, who published a monograph on "Bovista" in 1967. Kreisel also defined the "Lycoperdon""-type (a capillitium comprising long, threads with occasional dichotomous or irregular branches), and the "intermediate" type (a transitional form between the "Bovista" type and "Lycoperdon" type, featuring threads that may be pored, with several thick main stems connected by multiple branches). All three types of capillitia structure are found in "Bovista". "Bovista"-type capillitia are elastic, a feature shared with the gasteroid genera "Lycoperdon" and "Geastrum". The flexibility of the capillitium gives the gleba a cottony texture that persists even after the exoperidium has been sloughed off.
Systematics.
The genus was originally described by mycologist Christiaan Hendrik Persoon in 1794. He described the genus as "Cortice exteriore libero evanefcente, pileo acauli demum glaberrimo, vertice irregulariter rupto" ("Exterior cortex vanishes, cap stemless becoming smooth, irregularly breaking the top"). Synonyms include "Piesmycus" (Rafinesque 1808), "Piemycus" (Rafinesque 1813), "Sackea" (Rostkovius 1844), "Globaria" (Quélet 1873), and "Pseudolycoperdon" (Velenovský 1947). "Bovista plumbea" is the type species.
Kreisel, in his 1967 monograph, proposed two subgenera based on the type of capillitium. Subgenus "Globaria" has species of the "Lycoperdon" type, while subgenus "Bovista" is represented by the "Bovista"-type or intermediate capillitium. Further divisions into sections and series is based on the capillitium type, the absence or presence of pores in the capillitia, and the presence or absence of a subgleba (a sterile base). Phylogenetic analysis has shown that "Bovista", as defined by Kreisel, is monophyletic. Also, "Bovista" may be split into two clades, "Bovista" and "Globaris", that roughly correspond to the subgeneric divisions suggested by Kreisel.
Edibility.
Puffballs of the genus "Bovista" are generally edible when young and white inside, but caution must be taken to prevent confusion with immature, and potentially deadly "Amanitas". This is done by cutting fruit bodies longitudinally to ensure that they are white throughout, and do not have internal structures within.
Related genera.
"Bovistina" is a related but separate genus that was created to describe species with the external features of a puffball, but with the glebal characters of a Geaster. "Bovistella" is another similar genus, it may be distinguished from "Bovista" by its ample sterile base.
Use in homeopathy.
Reference to the genus has appeared in several 19th-century textbooks on homeopathy. Richard Hughes wrote in "A Manual of Pharmacodynamics" (1870) "Bovista is said to be indicated, and to have proved curative in head affections characterised by a sensation as if the head were enormously increased in size". In "Lectures on Clinical Materia Medica" (1887), E. A. Farrington claims that "Bovista" spores restrict blood circulation through the capillaries, and suggests uses associated with menstrual irregularity, or trauma. He also mentions that "Bovista" produces some symptoms of suffocation, and might be useful in remedying asphyxiation resulting from inhalation of charcoal fumes. Even more ailments have been suggested to be improved with use of Bovista, such as "awkwardness in speech and action", "stuttering or stammering children", "palpitation after a meal", diabetes mellitus, ovarian cysts, and "acne due to cosmetics".
Species.
The "Dictionary of the Fungi" (10th edition, 2008) estimates there are 55 "Bovista" species worldwide. Index Fungorum lists 92 species that it considers to be valid.