Stropharia and Hypholoma
Similarities and differences

Stropharia have well developed persistent veil, attached gills, and dark (purple-brown to black) spores.
The cap is usually viscid and some shade of yellow, orange red, blue or white.
The veil forms a distinct annulus (ring) on the stalk, and many times leaves copious remnats on the cap

Hypholoma have dark brown to purple-brown spore print, the absence of prominent veil remnants other than an occasional cortina or a few wisps of tissue on the cap margin).

While the size of the stipe can be similar, in most cases Stropharia will be taller and wider than Hypholoma. Stropharia tends to have fairly wide gills while Hyphaloma has somewhat narrow gills. While Hypholoma may be fibrillose, Stropharia is often floccose (i.e. covered with woolly tufts)- From: Dick B..

Stropharia
From Wikipedia:
The genus Stropharia (sometimes known by the common name roundheads) is a group of medium to large agarics with a distinct membranous ring on the stipe.

The scientific name is derived from the Greek word "strophos' meaning "belt", in reference to it. Spore print color is generally medium to dark purple-brown with white edge at maturity, except for a few species that have rusty-brown spores.

Stropharia rugosoannulata is regarded as exquisitely edible when young, is now the premier mushroom for outdoor bed culture by mycophiles in temperate climates.

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From Wikipedia:
Stropharia rugosoannulata, commonly known as the wine cap stropharia, "garden giant", burgundy mushroom or king stropharia (Japanese: saketsubatake), is an agaric of the family Strophariaceae found in Europe and North America, and introduced to Australia and New Zealand. Unlike many other members of the genus Stropharia, it is widely regarded as a choice edible and cultivated for food.

From Widipedia:
Hypholoma: Species in this genus are easily recognizable because the dark spores create a distinctive greenish effect on the yellow cap underside. Hypholoma means "mushrooms with threads" because of the thread-like veil that connects the cap to the stem when young and for the bundles of rhizomorphs which radiate outwards from the stem base. Sulfur Tuft (shown here) are Hypholoma fasciculare.

General characteristics of Hypholoma:
The fruiting bodies mostly have a central stipe. Some are medium-sized and there are also smaller species. The caps range in colour from yellow/brown to brick red.

The spore colour is dark brown to black.

The developing mushroom is enveloped in a veil, but in Hypholoma this can be seen only in very young examples. This means that there is no well-defined ring, and nor are there distinctive flakes on the cap, but there may be cottony ring zones on the stipe, sometimes coloured by the dark spores.

well-known species are H. capnoides and H. lateritium.

Hypholoma fasciculare is This saprophagic a small gill fungus grows prolifically in large clumps on stumps, dead roots or rotting trunks of broadleaved trees. The "Sulphur Tuft" is bitter and poisonous; consuming it can cause vomiting, diarrhea and convulsions.
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From Wikipedia:
Hypholoma capnoides is an edible mushroom which like its poisonous or suspect relatives H. fasciculare ("Sulphur Tuft") and H. sublateritium ("Brick Caps") grows on decaying wood, for example in tufts on old tree stumps. Anyone thinking to eat this mushroom needs to be able to distinguish it from Sulphur Tuft, which is more common in many areas. H. capnoides has greyish gills due to the dark color of its spores, whereas Sulphur Tuft has greenish gills. It could also perhaps be confused with the deadly Galerina marginata or the good edible Kuehneromyces mutabilis.

Taste is mild (other Hypholomas mostly have a bitter taste).

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