The lab of

C. Thomas Philbrick




The Riverweed Family











Funded by the National Science Foundation

& The National Geographic Society


Philbrick's Research

    My research relates to the biology, taxonomy and evolution of aquatic flowering plants.  I have published on topics ranging from aquatic plant reproductive systems, to the spread of invasive aquatic plants, aquatic plant structure, and the taxonomy of water starworts (Callitrichaceae) and riverweeds (Podostemaceae). 

   Over the last several years my research interests have focused on a family of aquatic plants called riverweeds.  Riverweeds are flowering plants that occur only attached to rocks in river-rapids and waterfalls.  One species occurs in eastern North America, whereas about 170 species occur in Mexico, Central America, and South America.  The geographic scope of my research at the current time includes southern Mexico through Central America, Venezuela and parts of Brazil.

    My research focuses on the biodiversity of riverweeds.  Specifically I am interested in gaining answers to the following questions.

    1.  How many species of riverweed are there and where do they occur?

    2.  How are species related phylogenetically?

    3.  Is the high incidence of endemism (i.e., species occurring in small geographic regions) real or an artifact of poor taxonomic understanding?

    4.  What elements of natural history (e.g., pollination biology, seed dispersal) influence species distributions?


Research Opportunities for undergraduates

    Funding from the National Science Foundation allows me to integrate undergraduate students into my laboratory and field research.  Several students are presently involved in my research on Podostemaceae.  I encourage students to come to talk with me about their possible involvement in my research activities. 


Venezuela: January 2005

Brazil: July-August 2005

Brazil: July-August 2006

Costa Rica: March 2006

Venezuela: January 2006


Summary by Genus for the above trips