Macrolepiota dolichaula is a large mushroom that can often be seen in open paddocks from some distance away. It occurs in the warmer regions of Australia such as the North Coast of New South Wales and Queensland. It also occurs in other countries such as Vietnam, Northern Thailand and China. In all those places it is also considered an edible species. Genetically, the specimens from Australia form a monophyletic clade with the species from China. DNA Barcoding shows a 100% match between specimens from Australia and China. This is shown by specimens lodged by the mycologist who specialises in this genus, Else Vellinga. Genetically, it sits close to Macroplepiota procera, with which it is often confused.
The epiphet ‘dolichaula’ comes from Greek ‘dolichos’ for long, and ‘aulos’ for tube, referring presumably to the stipe. It is conventional to pronounce ‘ch’ in Greek as ‘k’ in English. I pronounce this dolly-kola. People in Australia sometimes use the nickname ‘Dolly’ for this mushroom.
When it is young, the mushroom has is bell-shaped (campulinate) as shown in the image below.
The centre of the mushroom has a slightly raised area (an umbo) which often has a light tan colour. From the centre, the cap squamules radiate towards the rim, the spacing getting wider towards the outside. These are white to very faint yellow-brown. The whole cap at maturity is between 60 and 210 mm in diameter.
The gills are white to begin with, but darken to a straw colour over time. They are crowded and are not attached to the stem (free) and the length alternates between long (lamellae) and short (lamellulae).
As the cap expands, a partial veil extending from the edge of the cap to the stem breaks away. This membrane has a similar texture to the cap surface. At the edges of the cap, ragged remnants of this partial veil remain.
If it is not torn away completely, as in the above image, on the stem, the remains of the partial veil form a ring or annulus. This hangs downwards.
The stem (stipe) of the mushroom is often lightly covered with squamules rather like the cap. It tapers slightly from the base to the top and it is hollow. At the bottom of the stem, when cut or bruised will develop an orange/brown colour. It does not produce a bright red colour and does not form a colour at the top of the stem. The stipe also splits into vertical pieces. This can be seen starting to happen on the last picture at the bottom of this post.
People sometimes refer to these mushrooms as Parasols, or White Parasols but i prefer to avoid terms like this as they can lead to much confusion.
This mushroom needs to be distinguished from Chlorophyllum molybdites. With practice this is easy to do but for the beginner, the simplest test is to wait until a specimen matures and the gills of C. molybdites will be seen to develop a dark grey/green colour.
It also needs to be distinguished from Chlorophyllum hortense, a mushroom with smaller stature but similar appearance. This distinction can be made by the fact that Chlorophyllum hortense stains bright red immediately right through the whole length of the stem. Another feature that is less clear is that C. hortense has a striate margin, that is to say closely spaced lines at the edge of the cap.
In a book recently published by the CSIRO this species is listed as poisonous because of unspecified reports of bad reactions. Given that this mushroom is so easily confused with Chlorophyllum molybdites, I am confident that this mis-identification is the origin of such reports.
Within the Australian mushrooming community (not to mention China and Asia) this is regarded as one of the most popular and tasty of wild mushrooms. I am not aware of a single report of ill effects but I am aware of dozens of glowing reports regarding the edibility and taste.
