马勃是一类担子菌门的真菌通称，一般为球形，未成熟前是白色，成熟后为褐色，内部为粉末状。可入中药，用于止血。

以前的分类法将马勃统一列为一个腹菌纲（Gasteromycetes）或腹菌亚纲（Gasteromycetidae），但最新的分类认为它们实际是一个多系群的组合，他们共同的地方是都具有一个密闭子实层的子实体，在内部产生孢子，其孢子不是像其他蘑菇一样的掷孢子，而是稳孢子，也就是说当子实体成熟时不会将孢子抛出，而是子实体爆裂开，孢子如烟雾一样散出。马勃类可能是从伞菌类逐渐进化来的，现在已经不再把它们看作是属于同一个纲的品种。

A puffball is a member of any of several groups of fungi in the division Basidiomycota. The puffballs were previously treated as a taxonomic group called the Gasteromycetes or Gasteromycetidae, but they are now known to be a polyphyletic assemblage. The distinguishing feature of all puffballs is that they do not have an open cap with spore-bearing gills. Instead, spores are produced internally, in a spheroidal fruitbody called a gasterothecium (gasteroid ('stomach-like') basidiocarp). As the spores mature, they form a mass called a gleba in the centre of the fruitbody that is often of a distinctive color and texture. The basidiocarp remains closed until after the spores have been released from the basidia. Eventually, it develops an aperture, or dries, becomes brittle, and splits, and the spores escape. The spores of puffballs are statismospores rather than ballistospores, meaning they are not actively shot off the basidium. The fungi are called puffballs because clouds of brown dust-like spores are emitted when the mature fruitbody bursts, or in response to impacts such as those of falling raindrops. Puffballs and similar forms are thought to have evolved convergently (that is, in numerous independent events) from Hymenomycetes by gasteromycetation, through secotioid stages. Thus, 'Gasteromycetes' and 'Gasteromycetidae' are now considered to be descriptive, morphological terms (more properly gasteroid or gasteromycetes, to avoid taxonomic implications) but not valid cladistic terms.