We have gotten pretty good at getting DNA from dried samples (for example herbarium sheets). Cloning doesn't always work. You might be able to get to a callus

We have gotten pretty good at getting DNA from dried samples (for example herbarium sheets). Cloning doesn't always work. You might be able to get to a callus (undifferentiated mass of cells), but moving from that point to a something that looks like a plant, with roots and leaves and that can grow in soil requires a lot of trial and error. Also money; field botany gets almost no grant money. In fact, the NSF just recently decided to end dissertation improvement grants for most areas of field biology.