Today, I found more yellow fungi in my jessamine. Bright yellow!! To my surprised, I found three mushrooms, two about an inch tall, tapering towards the apex with a tiny yellow cap.
With the info that this fungus actually produces a mushroom, I was able to narrow my search and I think I've got it!! Leucocoprinus birnbaumii!!!
http://72.14.209.104/search?q=cache:Jq62mEBIoFgJ:www.mushroomexpert.com/leucocoprinus_birnbaumii.html+Leucocoprinus+birnbaumii&hl=en&gl=ca&ct=clnk&cd=1
If you look at the 5th picture down, a photo taken by Marta Barcelo, and see the tiny mushrooms in the back, this is what mine look like, but the cap is still even smaller on mine, so I assume they are very young.
The site says they often pop up in house plants or greenhouses that are very warm, we all know this is my case!! Site says they don't hurt the plant but doesn't specify whether they are beneficial or symbiotic towards the plant. They actually encourage you to let them grow, since they offer a very contrasting color to the green plant as a ground cover. Don't know if I'd go that far myself.
Anyways, maybe this is the fungus some of you saw in your pots, but never saw the mushroom as they never got that far in their life cycle.