Are there any plants, grass etc. that glow in the dark?
This article shows a picture of a beach in the Maldives glowing at night due to the action of phytoplankton.
At the moment there are no vascular or higher order plants like grass that glow in the dark naturally.
With a bit of genetic tinkering almost anything could glow in the dark.
I haven't heard of or seen plants that glow in the dark naturally, though some species of mycelium do naturally glow in the dark:
Some many years ago while camping somewhere in Minnesota we setup camp and used a large rotting log for a seat. When it got dark I started noticing some light from below and to our surprise the whole log was glowing. The glowing species must be common in that area because we started finding it all over the place.
I expect you read this article in New Scientist or one similar to it:
Kyle Taylor, a founder of Glowing Plant, splices firefly genes into plants and wants to demystify the process by showing you how to do it at home
. . .
So how do you make these plants glow? Essentially we take genes from bioluminescent organisms – such as fireflies and bioluminescent bacteria – and insert them into the plant. So the plants have an eerie blue-green glow.
How much light do the plants emit? Should I toss out all of my light bulbs? At this point, no. They are still pretty weak, but they are visible in a dark room. Plants didn't evolve to emit light, they evolved to absorb it. But you have to start somewhere, and this is our starting point.
It's not really about the plants, it's about demystifying GMO. That said, they got their kickstarter funding and now say they will start to ship this fall.
Along the lines of kevinsky's answer, there are some bioluminescent mushrooms, but these are of course fungi, not plants.