Chlorophyllum & Macrolepiota.

Basidiomycota > Agaricomycetes > Agaricales > Agaricaceae.
There are about 40 species of Macrolepiota and 20 of Chlorophyllum.
Macrolepiota has 3 species in Australia – M. dolichaula, M. eucharis and M. clelandii.
Chlorophyllum has 4 species – C. brunneum (was Macrolepiota rachodes), C. hortense,
    C. molybdites and C. nothorachodes.

Macrolepiotas are macroscopically very similar to some Chlorophyllum species.
C. molybdites, with a green spore print, is easily identified but microscopy of the spores
    and hyphae is needed to distinguish the rest.
Apparently many species of both genera have been incorrectly named.

Medium to large mushrooms found in leaf litter and lawns.
Caps are round, convex then flattish and some have a central umbo (hump).
Caps are white, cream or pale brown with brown scales and a large central, dark brown patch.
The gills are crowded, white (one species greenish) then brownish, mostly free of the stem.
Spore prints are white (one green).
The stem is central, with a ring or remnants from the partial veil.

Solitary or in groups.
They are fleshy, medium to very large mushrooms up to 20 cm or more in height.

The cap is ovate then conical then umbonate then slightly flattened.
The central brown umbo is prominent.
Surrounding this are concentric rows of brown scales on a white or cream background.
There may be tags around the cap margin from the partial veil.

The gills are white or cream, free of the stem and the spore print is mostly white.

Chlorophyllum hortense.
Medium to large mushrooms that grow in small groups or large masses on mulch, compost or dung.

Caps are up to 10 cm across, convex then flattening a little, striated around the margin.
They are cream or white with whitish, yellowish or brown scales which may be hard to see.
There is a darker brown or yellowish central umbo.

The gills are white then become brown with age and they may be greenish near the stem.
They are free of the stem and the spore print is cream or white.

The stem is white, central, and up to 7 cm high.
The base is swollen and there is a ring.
When damaged all parts rapidly bruise to red.

Chlorophyllum molybdites.
The Green-gilled or false parasol is a medium to very large mushroom growing in grassy areas.
Occasionally solitary but usually they are massed.
The cap can be up to about 15 cm across.

Young caps are brown and roundish or bell-shaped.
Older caps expand to become convex with a slight central umbo then become flatter.
The brown surface breaks down into dark brown irregularly scattered scales on a white, cream or pale brown background.
The scales are dense and darkest in the centre.
The edge often splits. The flesh bruises to red.

The gills are free of the stem and can be close or remote.
They are white, pale cream or pinkish when young then green or pale yellowish-green.
The spore print is green.

The stem, up to 15 cm high, has a swollen base.
It is white above the double ring and darker below.