When the mushroom is 9 mm tall you see it still enveloped in a veil. The bulge at the top shows you where the cap is developing but it is still concealed. The second photo (the mushroom now 17 mm tall) was taken 25 hours after the first and now the cap shows clearly, though it is yet to expand. Another 24 hours later you see that the stem has extended to 3 cm and the cap has expanded. The cap flesh is very thin and can shrivel quickly. This mushroom had grown from some damp wood that I’d kept in a lidded, plastic tub. When I took it out for the final photo the cap edge was a perfect circle but here you see it with a wavy margin. The cap is already beginning to dry out and shrivel. The brown hairs are composed of tufts of multi-celled hyphae and in the inset in the third photo I show such a tuft viewed through a microscope.