Pileus (Cap): 1.5 - 2(2.5) cm and hemispheric to convex to companulate. The margin is incurved when young, clay-colored, often reddish brown towards the disc, hygrophanous, smooth, and grayish to greenish; it is translucent-striate at the margin when wet. It becomes blue when bruised.
Lamellae (Gills): Adnate, close to crowded, at first gray-olivacous, becoming mottled and darkening to black with age.
Stipe (Stem): The stipe is 5%u201312 cm long, 2%u20133 mm thick, hollow, and vertically striate. It is blackish towards the base, greyish towards the apex, and pallid to whitish fibrils run the length of the stipe. The stipe is equal to slightly swollen at the base and lacks a partial veil.
Microscopic features: Spores are dark violet black to black, ellipsoid, and 10.5-12.0 x 7-9 um. The basidia each produce two spores.
Season: In the spring or during the rainy seasons.
Habitat and Distribution: Panaeolus tropicalis is mushroom that grows on dung. It is most often found in Hawaii, Central Africa, and Cambodia; it can also found in Mexico, Tanzania, the Philippines, Florida, and Japan.
Growth Habit: Solitary to scattered.
Bruising: The entire mushroom readily bruises blue where it is handled.