Multiple realities(covers information from several alternate timelines)
Bonsai was the Asian art of aesthetic miniaturization of trees by growing them in containers.
The classroom aboard the USS Enterprise-D had several different Bonsai trees. (TNG: "Reunion")
Wesley Crusher had a Bonsai tree in his guest quarters on board the Enterprise-D in 2370. (TNG: "Journey's End")
In an alternate timeline, Captain Beverly Crusher kept a bonsai tree in her ready room aboard the USS Pasteur. (TNG: "All Good Things...")
Keiko O'Brien had a number of Bonsai trees in her quarters aboard Deep Space 9. (DS9: "If Wishes Were Horses")
Keiko O'Brien's Bonsai trees were killed while under the care of her husband, Miles O'Brien, while she was visiting the Fire Caves on Bajor in 2373. Doctor Julian Bashir, trying to be helpful, accidentally killed them by over watering. Keiko had been caring for the trees, which were Idran hybrids, for years. (DS9: "The Assignment")