XVI International Botanical Congess

The New York Metropolitan Flora is a comprehensive survey of plants within 50 miles of New York City. Nearly 3000 species are found in this habitat-rich area. Distribution data documents movements of introduced and native species. Several distinct patterns associated with urbanization can be seen. Some species, such as Paulownia tomentosa, are restricted to the urban core. This may be related to urban climate or other habitat requirements. Many native species have declined in the urban areas. Some of these may persist in the larger city parks which act as island refuges. Others have declined even in the larger parks. Few members of the Ericaceae currently occur in NYC proper, even though some of them, including Kalmia spp. and Leucothoe racemosa, are widespread in the surrounding regions. It is hypothesized that soils have changed affecting pH and mycorrhizal associations.