Macrolepiota dolichaula or the white parasol is one of Australias most regal agarics as the photo above shows there are few fungi that are more pleasing to look at or more photogenic. They appear in paddocks and roadsides occasionally over summer then in great flushes in autumn, their tall white caps stand out against the green grass and they can be seen from kays away. While most folk call them toadstools and some death caps! These fungi are actually very closely related to the parasol mushroom, macrolepiota procera, known as a prime edible in Europe and the US. DNA studies have put m. dolichauala, m. procera and the other Australian macrolepiota clelandii in the same clade due to their genetic similarities. The best available scientific paper on Australian macrolepiota and chlorophyllum can be found here.
Most people, myself included struggle with the fact that Macrolepiota dolichaula is actually a really good edible mushroom. Fresh they have a spongy texture and a rather strong smell that just screams out ‘toadstool!’ but once they are cooked they become rather delicious. I must stress that it really is important to be sure of the ID of these mushrooms because they have quite a lot of unpleasant lookalikes that from my experience often grow nearby. The three most common lookalikes are Chlorophyllum molybdites, Chlorophyllum hortense and a few of the large white amanitas. Some of the key features on m. dolichaula are as follows, the large size and long stem, often twice as long as the diameter of the cap, Its hollow and fibrous, stains slightly brown with a large floppy and movable ‘double’ ring, the golden brown umbo and scales and the white gills and spore print. The snake like scales on the stem are not always present. I find two variations of m. dolichaula, one with a longer thin stem and much finer scales on the cap and stem and one that is shorter and stockier with more and larger scales on the cap and the snake skin pattern on the stem. I have sent away the two variations away to see is a there is a genetic difference as well. For a full description of Macrolepiota dolichaula.
While I most often see this mushroom in cow paddocks and on roadsides I have also been finding it growing in coastal heath among native vegetation. Sometimes only a single mushroom, sometimes small groups and sometimes huge rings in the grass. M. dolichaula grows in India and through parts of Asia where it is eaten and some attempts have been made to cultivate it. There are only a few images from Asia and India and their version looks quite different to ours, perhaps the DNA analysis will shed some light onto their similarity but at this stage my assumption is that the local m. dolichaula is native to Australia and not introduced from Asia or the sub continent. This is a highly nutritious mushroom and well worth becoming familiar with.
Update: The DNA results are in, short stem, 99% Macrolepiota dolichaula (KP859148) long stem 100% Macrolepiota dolichaula (KJ643334) The match was to a sample from Thailand.