How old are plant species and are there extinct ones?

[Rogin the Armchair fan]

We all know about how animals have evolved, how sharks are pretty much the same now as they were at the time of the dinosaurs while most mammals began as a type of small vole. Do we know the same about plants? The conifer trees in my garden, for example, are they pretty much the same as ones that would have been around 5 million years ago? Or 150 million?

[hobbes]

Well flowering plants only appeared 125 million years ago, so there's that.
But yes, they evolve, often in relation to the animals around them so that they can distribute pollen ((that's why nectar exists and their colouration) or in competition with other plants.
Or of course through genetic modification by humans or animals.
Wheat used to be grass, after all.

[Sits]

We have one of the tree fern varieties growing in our garden and it always reminds me of the cycads in my kids’ dinosaur books when they were little. And sure enough they are a very old group of plants:

[Guy Profumo]

Aren't most of the plants preserved in our coal lumps all extinct?

The ones around at the time of the dinosaurs?

[matt j]

Loads and loads of extinct plant species, many prehistoric ones are often used as index fossils.

A lot of botanical gardens have species considered extinct in the wild, it becomes a matter of picking a favorite. I like this one, if just for name: https://www.google.com/search?q=Cyanea+superba

[Satchmo Distel]

"Nearly 600 plant species have gone extinct in last 250 years."

https://news.mongabay.com/2019/06/ne...ast-250-years/

[Hot Pepsi]

Plant seeds are easier to preserve than animal DNA, I suppose, but wasn’t there a recent huge disaster where one of the refrigerators that hold all the seeds melted?