Frequent heavy showers.
A series of images comparing Suillus luteus (Slippery Jack) with Suillus flavidus.
Suillus luteus on the right in each image.
The caps are equally viscid, but it shows up more on the luteus: Caps 5 cm and 10 cm. respectively.
The ring on flavidus is a transparent orange jelly. The ring on luteus starts as a conventional frill, but quickly degenerates into a dark mass.
It can easily be seen that the pores of flavidus are much larger and more angular. In fact, this is what drew my attention to it in the first place.
These two images are to the same scale. The flavidus pores are compound, with one exit tube being the opening for a number of smaller tubes.
Suillus luteus and Suillus flavidus are both Pine associates. Flavidus is here shown about 3m. from the closest Pine. Whereas luteus is rather common, flavidus is very rare: this is the only known location outside a couple of forests in Scotland, although it has now spread to 4 patches covering a stretch of about 400m.