The 2012 checklist gives 17 British species of Mordellidae, but this is a taxonomically-confused group, with several recent descriptions and synonomisations from the British fauna.  As a group they are distinctive: oval-elongate, pubescent brown or black beetles, 2-9mm long, with an extended, elongate pygidium reminiscent of a sting.  Adults are characteristically found curled in a c-shape on flowers, where they feed on pollen.  When disturbed, their general escape mechanism is to skip about and tumble from the flowers, hence their vernacular name.

17 species of small to medium-sized (3-16mm), oval to elongate-oval beetles, found in association with fungi and fungoid bark, particularly in ancient woodland.  Generally black or brown in colour, some are brightly coloured or patterned: Conopalpus testaceus (Olivier) has a bright orange pronotum while Osphya bipunctata (Fabricius) have a red and black striped pronotum and legs.  All the British species are rare, and all but Orchesia undulata Kraatz have conservation designations. 

A family with four British representatives, all 3-4mm species found in association with decaying fungi, on which they feed.  One species (Hallomenus binotatus (Quensel)) has recently been transferred to Tetratomidae from the Melyridae.

A family of 22 small (1-3mm) nondescript brown or black beetles in Britain, strongly associated with fungi and very rarely found away fungoid situations.  Most species are associated with particular genera of bracket fungi, particularly Trametes, Ganoderma, Piptoporus, Fomes and Stereum spp., and can be abundant within them.  Several species are scarce (e.g. Cis dentatus Mellie and Cis jacquemarti Mellie) but many others are widespread and can be common, including the non-native Cis bilamellatus Wood, an Australian species first found in Britain at Kew Gardens. 

Generally small (1-6mm) beetles, there are 15 species on the British list.  They are usually associated with fungi and are consequently found in rotting wood and decaying plant material.  Generally parallel-sided elongate-oval in shape, the hind margin of the flight wings is fringed with a series of long hairs.  Generally brown or black in colour.

Small to very small beetles (1-3mm), there are 56 species in Britain.  Generally brown to reddish-brown, they have a rather characteristic appearance, with an angular pronotum and a rather fat-bottomed appearance as the striate elytra bulge out towards the apices.  They are found in a diverse range of habitats including compost heaps and leaf litter, fungoid bark, rotting fungi, mature Myxomycetes, and indoors in mouldy areas of plaster, wallpaper, wood, etc.  Dissection is required to reliably identify many species.

This family of minute (0.5-1.3mm) beetles has 11 species on the 2012 checklist, but a twelfth species (Arthrolips obscura (Sahlberg)) was added in 2013 by Tony Allen and Andrew Duff.  Similar in appearance to the inconspicuous coccinellids, they are mould-feeders and are usually found under fungoid bark or in piles of rotting wood or vegetation, though Orthoperus atomarus (Heer) is synanthropic, occurring in wine cellars on mouldy corks.  Most species are southern in distribution, and identification relies heavily on the elytral microsculpture and genitalia dissections.

A small family, with eight British species, oval to elongate-oval in shape and between 2 and 6mm long.  Five of the species found in Britain are small and brown but the three larger species are more brightly coloured. These three include the false ladybird, Endomychus coccineus (L.), which resembles a ladybird (Coleoptera: Coccinellidae) in shape and colouration.  Mycetaea subterranea (Fabricius) can be a minor pest in grain stores but the family are mostly found in association with fungi, including within puffball (Lycoperdon spp.) and earthstar (Geoastrum spp.) fungi (Lycoperdina spp.), beneath fungoid bark and in leaf litter.

The sole British representative of this family, Sphaerosoma piliferum (Müller) is a tiny species, around 1.3mm long.  Red-brown in colour, with yellow pubescence, it is largely hemispherical in shape and rather similar in appearance to the smaller ladybird species, though it can be distinguished by the longer, clubbed antennae. It is a fungivore and is often found in leaf litter or decaying wood.