Smithsonian National Museum of Natural History

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Department ofBotany


 Map of the Flora of the Flora of the Washington-Baltimore Area

 Historic DC Map of 1917

 DC Gazetteer of collections localities

The first-flowering dates for spring-blooming plants (both native/naturalized and cultivated species) have been recorded by more than 100 volunteers in the Department of Botany, NMNH, each year from January 1 to May 31 since 1970. The two main contributors have been Aaron Goldberg and the late John Wurdack. The spring flowering list is updated and compiled on a yearly basis from these records. The list gives the range of dates that the spring flowers have been observed to start blooming within the Washington area over the years 1970-2010. A few non-flowering plants (ferns, gymnosperms) are included, and for them the dates refer to spore- or pollen-shedding.

    In March 2000, Smithsonian scientists Stanwyn Shetler, Mones Abu-Asab, Paul Peterson, and Sylvia Stone Orli released the results of their study, "Earlier Plant Flowering as a Response to Global Warming in the Washington, DC, Area". The study indicates that the rise in the region's average minimum temperatures is producing earlier flowering in 89 of the 100 common plant species investigated. For the full story, see the press release. Their paper was published in Biodiversity and Conservation in 2001. An earlier paper, "First Flowering Dates for Spring-Blooming Plants of the Washington, D.C., area for the years 1970 to 1983", by Stanwyn Shetler and Susan Wiser, is also available as a pdf file.

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