When the provenance of a plant comes under discussion, it is usually part of an attempt to decide if that particular plant will be suitable for a particular location. For example, while many species are hardy in USDA Zones, say 6-9, a plant that came from Central Florida (Zone 9) may not be hardy in Central Pennsylvania. But it might. But it might not. Anyway there's another sense of the word. When antique dealer's use the word, they are referring to the personal ownership history of an item. I like knowing where my plants came from. Sitting here looking out the window into the back garden, I can see an old Sky Pencil Japanese Holly that was given to me in 1992 by Gene Eisenbeiss. Gene was a horticulturist at the National Arboretum for over 25 years. He was the international registrar for cultivated Hollies for I don't know how long with a long list of publications. He was an incredible resource for information, much of it about hollies, and an incredibly pleasant person. I like having that plant.
If the banana weren't in the way I could see a potted gardenia standard that I have had for...I guess about 25 years. It was a gift from a customer at Behnke's when I worked there in the early 1980's. She had to get rid of it because her son was allergic to many chemicals and Gardenias are hard to maintain without using pesticides. Over the years its trunk diameter has gone from about 3/4" to 4". Ironically, I haven't used any chemicals on it in years. It lives in our semi-heated basement all winter and somehow stays clean!
Sometimes its fun just to remember where you bought a plant a long time ago. The 30' Parrotia I see through the front door came, as a ~18" one-gallon potted specimen from Susannah Farms Nursery in Poolesville about 20 years ago. I bought it on the first trip I made there along with a dwarf cultivar of Pinus strobus (I have lost the name) that is still less than 3' tall, and a fastigiate Taxus 'Beanpole'. Memory Lane.
But while 20 odd years may be impressive to younger folks, I still have a few succulents that date back to my first infatuation with them in the late 1960's; that means 40 year old houseplants. Wow. I must be old.