Though potentially of great scientific interest, conifers, as a group, are not well studied, mostly because of the inavailability of research material. In much of the world, conifers tend to be difficult garden subjects. In general they are highly intolerant of air pollution and poor-quality irrigation water. Some cannot tolerate summer rain. Others cannot tolerate frost.
Few areas can grow more than a small number of species.
In establishing its conifer collection, the Arboretum capitalized upon its remarkable horticultural potential. The collection contains representatives of all nearly all known genera of conifers, with the exception of a genus unknown outside of China and a parasitic New Caledonian genus. They are of unusual interest because of the unlikelihood that ample fossil evidence of the earliest flowering plants will ever be found. It has attracted scientists from far corners of the world and is now being used by molecular systematists, who hope to use modern methods to shed light upon the origins of flowering plants. This exhibit contains unusual fruit-bearing plants.