My son was given the below plant by his teacher a few years ago. At the time it was about 2 - 3 cm round and in a tiny plastic pot. It lived on a window sill and about two years ago it turned brown, looked really sick and we noticed the soil was all but dust. So I placed it in the bigger pot and we have given it an overdose of TLC to this day.
The thing is we don't know what type of cactus it is. Also, for the first time a flower appeared two days ago. It opened mid-morning and closed mid-afternoon, possibly because that's when it was exposed to sunlight. I am intrigued and fascinated by her beauty and how she is developing.
Is anybody able to let me know what type of cactus it is and the story behind the flowering, please?
Oh and BTW, I am going to transfer it into a bigger pot soon and yes, I need to fix my fence LOL.
Thanks Lyndal. I must confess I didn't know the leaves are a weed. It appeared around the time the cactus started thriving and producing the buds, so I thought it might be part of the cactus. I also didn't know about the moss. I have another pot with about five different cacti that have long outgrown the container. I have to re-pot them separately and that will be very tricky because one of the cacti has spikes too and they hurt like h*ll. I'm off to Bunnings in the morning. 
