Disciotis venosa

May 9, 2022

Good evening, friends,

This week’s fungus is Disciotis venosa, commonly known as the veined cup or the bleach cup. This cup fungus was found in Manitou on 4/25/2022. It is one of several brown cup fungi that pop-up this time of the year. Without microscopic evidence we can’t confirm the ID, but we’ll certainly delve into other possible identities below. The former president of the New York Mycological Society, Tom Bigelow, half-suggested the D. venosa identification over zoom and that made it fit enough to blog.

Fun Facts

D. venosa is in the family Morchellaceae, closely related to the well-known, highly coveted true morels. In fact, D. venosa is known as a “cup morel” and it is said to be just as tasty as the aforementioned morels. The issue remains that I can’t confirm the identity. If this little cup happens to be in the genus Gyromitra, instead, it could contain the compound gyromitrin. When metabolized in the stomach, gyromitrin turns into monomethylhydrazine; a toxic, volatile compound used in rocket propulsion (i.e. jet fuel). I’ll stick with my leftover lo mein.

D. venosa is said to smell like bleach (hence the name “bleach cup”), but that was not the case with this specific specimen. It could be due to age that it lost its smell – if it ever had one. When young, D. venosa starts out cup shaped and then flattens into the saucer shape you see below. I believe the darker margin on the saucer is also a result of age. However, with age, it is also supposed to develop fleshy, vein-like ridges in the center. You can see below the ridges in our specimen are rather small and nondescript.

Enough is known about D. venosa to understand that it prefers to grow on slopes. This coincided with where I found the specimen – on a slope in mixed woods (near two sugar maples and a tulip poplar). Unfortunately, we can’t solely look to that diagnostic for identification confirmation, and if we did, well, it sure would be a slippery slope…


D. venosa is thought to be both mycorrhizal and saprobic (as is the understanding with morels). It fruits in the spring and is found in temperate forests throughout North America and Europe. Instead of releasing spores through gills, teeth, or pores, it is an ascomycete which means that the spores develop within a sac-like structure called an ascus (plural: asci).

Gyromitra Leucoxantha and Gyromitra perlata are two similar species. All three fungi share a similar habitat – mixed woods on or near rotting wood – and a similar season of growth. The color, size, and short pseudo-stem suggest the D. venosa ID, but without microscopic evidence we’ll never know for certain. I’ve saved this specimen and I’ll scope it once I get the Mushroom Monday lab up and running :). 

In the News

The state government of New York is mulling over anointing Lactarius Peckii the official state fungus. You can read more about the bill, and endorse it with an ‘Aye’, here.

The first annual mushroom festival at the Rosendale Theatre in Rosendale, NY is occurring this Saturday, 5/14. Find out more here.

I was going to do a walk in Central Park this Saturday, 5/14, but life has gotten in the way – as it is known to do from time to time. No fret, I’ll be looking to bop down there the weekend of 6/4-6/5 instead. Pencil that one into your calendars if you want to hang out in the ramble and look for fungi. There will likely be more mushrooms to find later on in the spring anyway.

Late one tonight – the nicer the weather is outside, the harder it is to write during the day,

1) Kuo, M. (2006, April). Disciotis venosa. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/disciotis_venosa.html.
2) https://www.mycoquebec.org/bas.php?l=r&nom=Disciotis%20venosa%20/%20Pézize%20veinée&post=Disciotis&gro=86&tag=Disciotis%20venosa
3) https://www.aldendirks.com/research.html
4) https://botit.botany.wisc.edu/toms_fungi/may2008.html
5) https://www.inaturalist.org/taxa/126911-Disciotis-venosa
6) https://www.fungusfactfriday.com/139-disciotis-venosa/