Complex sentence: A staff of 200 trains 42 doctoral students at a time from all over the world; since the 1890s scientists from The New York Botanical Garden have mounted about 2,000 exploratory missions across the planet to collect plants in the wild.
Split into simpler sentences: A staff of 200 trains 42 doctoral students at a time, from all over the world. Since the 1890s, scientists from The New York Botanical Garden have mounted about 2,000 exploratory missions worldwide to collect plants in the wild.