“Brazilian Modern: The Living Art of Roberto Burle Marx” has taken over the New York Botanical Garden — and offers an exuberant gust of tropical modernism that will thrill anyone caught in the concrete jungle. Burle Marx, Brazil’s greatest landscape designer, hasn’t lacked for institutional attention lately; just three years ago the Jewish Museum presented a retrospective of his paintings, tapestries, jewelry and designs for green spaces and public thoroughfares in Rio, Brasília, and even Miami. But that show could not offer what this one does: a full-scale, fragrant, enchantingly lush garden, complete with numerous flowering plants and philodendrons that Burle Marx himself first identified.