I want to know the answer to the following question:
Why were new plants arriving in Europe in the 18th century?
All the background I'm provided with is that "During the 18th century, systems of plant identification were developed comparable to dichotomous keys, where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters.". Is that enough to answer the question?