The reef and rainforest ecosystems that students visit in the “Tropical Field Biology” course are incredibly diverse. Professor Scott Shumway offered field notes on a few of the species that students often focus on during the trip:
Pentaclethra macroloba—Not only is this tree one of the tallest trees of the forest, it is also the most abundant tree at La Selva. It is a member of the legume family and has large bean-pod fruits and large seeds. What are the secrets to its success?
Walking palm (Socratea)—Understory palm with stilt roots that give the impression of it being able to walk across the forest floor. (This is one for “Mythbusters!”)
Understory palms—Palms are the most abundant trees in the forest understory. Some never exceed a few meters in height, while others hold out for years waiting for an opening in the canopy to let in enough light for them to grow taller. Welfia, Socratea, Iriartea and Geonoma are common genera.
Canopy emergent trees—These are the giants of the forest. Awesome to behold, frustrating to identify, as all you can easily see is a massive wall of tree trunk. Buttresses at the base appear to help hold them up, but do they really? Ex: Dipteryx and Ceiba.
Epiphylls —Tree leaves are often covered with tiny plants (liverworts) and lichens known collectively as epiphylls. The epiphylls clearly reduce the amount of sunlight reaching the tree leaf. The apparently negative impact on the host leaf may not be so bad, as nitrogen-fixing bacteria are often associated with the epiphylls. Some leaves will be completely covered with epiphylls, while others will remain clear of epiphylls. How come?
Epiphytes—Epiphytes are plants that live on other plants. Tropical trees are draped with epiphytic plants belonging to a variety of different families. The most common epiphytes are orchids, tank-forming bromeliads, members of the arum family (Anthurium, Philodendron, Monstera) and ferns.
For more information on these and other plants, as well as photographs and illustrations, you can visit the website RainForest Plants, which Professor Scott Shumway has created with help from a colleague and Wheaton students, and support from a Patricia Higgins Arnold ’66 and Christopher B. Arnold Faculty Enrichment Award, a Wheaton Faculty Scholarship Award and the Andrew W. Mellon Foundation (wikis.wheatoncollege.edu/rainforest/).