A family of gilled basidiomycetes containing both native and introduced species in New Zealand, including Agaricus, Chlorophyllum, Leucoagaricus, Leucocoprinus, Macrolepiota, and several smaller genera.

Morphology
Fruitbodies- predominantly agaricoid (cap + stipe), though gasteroid and secotioid forms also occur.
Caps- smooth to scaly, flat to umbonate; often with a partial veil leaving a ring on the stipe.
Gills- thin, typically free from the stipe; initially pale, darkening in some genera (e.g., Agaricus - chocolate-brown).
Stipe- central, usually with a membranous annulus; volval structures absent except in a few secotioid/gasteroid forms.
Spore print- highly variable: white, greenish, ochraceous, pink, sepia, or dark brown; never rusty-brown or cinnamon-brown.

Ecology
Primarily saprobic, decomposing leaf litter, wood chips, dung, and other organic debris. They play a major role in nutrient recycling in forests, grasslands, and urban habitats. Some species occur in mulched gardens and disturbed sites, while others are associated with pasture or native forest soils.

Distribution
Cosmopolitan, with numerous species introduced to New Zealand through horticulture, forestry, and soil movement. Several native species remain poorly studied and unnamed, especially within Agaricus and Leucoagaricus.

Agaricus is a large, cosmopolitan genus of saprobic gilled mushrooms characterised by free gills, a partial veil, and a dark brown spore print. Species range from small and delicate to large and robust, with many New Zealand taxa still undescribed or poorly known. The genus includes familiar edible species as well as several toxic look‑alikes.

New Zealand Context:
New Zealand hosts a mix of introduced and native species. Several common lawn species belong to the Agaricus campestris and A. arvensis groups. Native forest species occur but are poorly documented, with multiple unnamed taxa known from herbarium collections. Rapid yellow‑staining species with phenolic odours are frequent incounted in disturbed habitats.

These are Agaricus species that I have not been able to identify beyond the genus. This is most likely due to the species not having been described (named).

Lepiota and allied fungi are fleshy saprobic gilled fungi similar in macro-characters to the Agarics but with a white or pale spore print. Gills are free from the stem with partial veils that typically leave a ring on the stem that may be loose. The spores are smooth and dextrinoid under a microscope. Some members are good for eating while others are poisonous. Unfortunately, this group of fungi has never been studied in New Zealand, thus many are not named. 

Those that are named have been introduced or are also native to Australia. It's a challenge to place them in the right genus and needs careful study of the keys. 

The different genuses can be identified by:
Chlorophyllum - large, shaggy mushrooms whose stems stain orange when cut or scratched.

Leucocoprinus - Tthe smallest (<5cm across) and most delicate with a well developed ring and somewhat granular membranous scales on the cap but not truly cottony. Often with striate margins in age. Clamp conections on the hyphae

Cystolepiota - small (<5cm across) mushrooms with cottony scales (that might wear off) and a poorly developed ring. Never striate. now known as Pulverolepiota.

Leucoagaricus - with either no cap scales or regular membranous scales. Leucoagaricus is more likely to be larger then Leucocoprinus. No clamp conections on the hyphae

A genus of small to medium-sized agarics with free gills, a persistent ring, and a white spore print. Species range from delicate to moderately robust. Saprobic on soil, litter, compost, lawns, and woodchips. Occur in gardens, parks, forest, and disturbed habitats.

Although Leucoagaricus fruitbodies are very common early in the season in lowland podocarp and beech forest, very few native species have been formally named. This is one of the most conspicuous “unresolved genera” in the NZ agaric flora. They are often more delicate and thin-fleshed than the introduced lawn species like Leucoagaricus leucothites.

A genus of small to medium-sized, delicate parasol mushrooms with free gills, a thin, fragile ring, and a white spore print. Species are typically thin-fleshed, often striate at the margin, and many have powdery, floccose, or granular surfaces. Most species are saprobic, thriving in warm, humid, nutrient-rich environments such as compost, potting mix, greenhouses, and forest litter

A genus of small to medium‑sized, wood‑inhabiting agarics with white spore prints and characteristically spiny spores.