Herbarium specimens such as those at the National Herbarium are also used by researchers to extract DNA from plant tissue. Such a study would be akin to populations genetics studies described here using historical specimens. My purposes here were to look at blooming time from herbarium records of R. viscosum in the DC area. Most of the 100 or so specimens I looked at were taken in full bloom, with blooming dates that varied year to year from 1876 until 2004. I will look for correlations between monthly temperature averages in the DC area and how this affects the blooming time in this species, if at all. This will help inform us about the variation I've observed across the country for flowering: it could be dependent on temperature in a given month, or not. Historical records will help us to determine this. From a practical standpoint, this knowledge will help us to determine how useful breeding for later or early blooming time could be. If it is not strongly dependent on the weather in a given year, my field observation would support a genetic component to this trait based on the range of blooming times within populations that we could alter through directed breeding.
This blog is the scientific narrative of a plant collection expedition, specifically for Rhododendron viscosum (Clammy Azalea) throughout the southern and eastern United States. My graduate research is focused on soil chemistry as a driving force for evolution and speciation in plants. Given the observational nature of this research, I turn to the wild for insight. I welcome comments or questions at susko004@umn.edu
Thursday, July 3, 2014
US National Herbarium
I've been working with the Smithsonian's Natural History Museum in Washington, DC over the past week. The museum maintains the US National Herbarium, spanning the top two floors of the building and houses around 5 million dried plant specimens. Not many people have heard of it: the area is highly secure, climate controlled, and open only to researchers with permits. So why has it existed since 1848? In the history of people studying plants, herbaria were prime resources for documenting species discovered in unexplored parts of the world. Explorers would go out looking for plants, harvesting branches and flowers to be dried for storage in an herbarium. These plant records could then be used as standards by which to determine new species or subspecies, again as all of this was done visually before our understanding of modern genetics. This led to the careful preservation of plant samples for future study. Most of these herbaria were commissioned by universities, botanic gardens, governments, or private individuals.
Subscribe to:
Posts (Atom)
© Regents of the University of Minnesota. All rights reserved. Equal opportunity educator and employer.