Stinkhorn

Sometimes called the witch's egg, the immature stinkhorn is whitish or pinkish, egg-shaped, and typically 4 to 6 cm by 3 to 5 cm. On the outside is a thick whitish volva, also known as the peridium, covering the olive-colored gelatinous gleba. It is the latter that contains the spores and later stinks and attracts the flies; within this layer is a green layer which will become the 'head' of the expanded fruit body; and inside this is a white structure called the receptaculum, that is hard, but has an airy structure like a sponge. The eggs become fully grown stinkhorns very rapidly, over a day or two. The mature stinkhorn is 10 to 30 cm tall and 4 to 5 cm in diameter, topped with a conical cap 2 to 4 cm high that is covered with the greenish-brown slimy gleba. In older fungi the slime is eventually removed, exposing a bare yellowish pitted and ridged surface. The rate of growth of Phallus impudicus has been measured at 10–15 cm per hour.