I have an improved meyer lemon tree in a pot next to my pool. It's in a greenhouse where I have been growing many different plants in pots. It recently began growing mushrooms on top of the mulch.

As mulch, I have moss (store bought) and pine needles from my yard. Also, I do use some mushroom compost in other pots in the greenhouse.

Questions:
1) What type of mushroom is this?
2) Will they damage the plant or its fruit if left there?
3) Will the mushrooms help the plant?
4) Are these mushrooms edible?

Any insights would be very appreciated as I am new to growing citrus, studying mushrooms, and growing in greenhouses.

Thanks!

they are more than likely HELPING the plant by breaking down organic matter and making the nutrients more readily available for the tree, they may also be helping the tree to get water

they dont look like anything edible to me

but i couldnt tell you with exact certainty because that pic doesnt do enough to identify to mushroom to my eyes
for a lot of mushrooms you require a spore print (just cut a mature cap off at the stem and place it on a green piece of paper or glass (white works but some spore prints are white and hard to see whereas i know of no spore prints which are green) and cover with a bowl or jar to keep wind off for 12-24 hours

also take very detailed notes of everything from the cap color, shape, texture and the stem color, shape, texture, and whether or not there are remnants of a ring around the stem
when you get done observing everthing you can above ground then when you remove the mushroom you take for the print, gently pinch the base of the stem and pull it fro mthe soil, see what color the mycelium is that clings to the base, most will be white but not all

basically there are millions of shrooms in the world, thousands of which are yet to be identified, and most of them cannot be identified from a simple picture, if you really really want to know your best bet is to contact a local mycologist in your area and get either a fresh or dried sample to them to look at for you

Those look a lot like Coprinus plicatilis, the pleated inky cap, or a close relative called Coprinus ephemerus, which grows on straw, dung and compost. Under "edibility", the pleated inky cap is described by David Arora as "unequivocally inconsequential due to its thin flesh". But Devon is correct- this mushroom is helping to break down compost in your potting soil/mulch so that your lemon tree can digest more nutrients. I see various species of coprinus mushrooms in my compost piles all the time. They like nitrogen, especially from urine and manure.

thanks M.K.

always have a great answer thats one step ahead of what i got when i answer, ive read aroras book now though i dont own it so hopefully ill be a bit better at id than i used to be but its always nice to see your replies behind mine

Also is possibly Parasola lactea. No doubt it is helping things if the tree's roots are healthy.