> And now, a team of scientists has sequenced one of the seed’s DNA—the oldest-yet genetic code recovered from a plant. The genome reveals the seeds belonged to a 6,000-year-old wild watermelon
Meanwhile, in 2003 https://www.scientificamerican.com/article/sediment-cores-yi... said
> Researchers have retrieved from sediment cores plant DNA that is nearly 400,000 years old--the oldest such specimen ever recovered.
and in 2012 https://www.nationalgeographic.com/science/article/120221-ol... said
> 32,000-Year-Old Plant Brought Back to Life—Oldest Yet
I'm sure there are other examples too.