Sunday, 21 August 2016

Green Elf Cup Season

I nipped up to Llwydcoed for an hour or two, this afternoon. The primary reason was to collect a second specimen of a rare rust I had found on acorn cups, last Sunday.

Oak Rust (Cronartium quercuum) Uredosori, discharging orange Uredospores.

The first specimen, when examined under the microscope, threw up a mystery, because all of the spores I measured (a couple of dozen) were way over the size given for Oak Rust in the books. They were, in fact, large enough to be of the American form of it. As the spore producing organs (uredosori) are supposed to be found mainly on the leaves, I wanted to collect some of those, in the hope that those spores would be closer to the normal size for our Oak Rust.
On getting back to the tree, I found that more of the acorn cups were developing the rust, but search as much as I liked, I couldn't find any uredosori on the leaves; so another mystery.

As I was searching the oak leaves, the rain arrived, so I packed up and headed for the car, but as I got to Cwm Nant-y-Gwyddel, it stopped, so I went in there to look for slime moulds. No slime moulds were seen before the return of the rain, but I was pleased to see that the Green Elf Cups were just starting to fruit and looking really good.

Green Elf Cup (Chlorociboria aeruginascens)


  1. Nice shots Mark and amazing stuff.

  2. Thanks Martin. If you want me to show you it (I couldn't begin to describe how to get to it), email me and we'll arrange to meet up. That goes for any of the 3V Birders, by the way.

  3. Thank you mark and i would like to see it .