Esther Jackson is the Public Services Librarian at The New York Botanical Garden’s LuEsther T. Mertz Library, where she manages Reference and Circulation services and oversees the Plant Information Office. Richard Abbott, Ph.D., is a botanist at the Botanical Garden, where he works primarily on updating the Manual of Vascular Plants of Northeastern United States and Adjacent Canada.
Acer pseudoplatanus by Frank Vincentz
Ontogeny recapitulates phylogeny doesn’t exactly flow off the tongue unless you are familiar with scientific terminology. However, what appears to be a somewhat intimidating phrase is actually marvelously succinct and elegant.
Ontogeny is “the development or course of development, especially of an individual organism.” This could refer to the development of a plant from embryo to seed to seedling to mature, reproductive plant. Or it could refer to an animal growing from an embryo into an infant and then into an adult.
Phylogeny is “the evolutionary history of a genetically related group of organisms, as distinguished from the development of the individual organism.” Sometimes these relationships are illustrated as trees of information, with groups of closely related organisms called clades. Studying and depicting shared evolutionary history is known as cladistics. Have you seen Darwin’s tree of life?
If so, then you understand the basic idea of phylogeny. It’s all about the study of relationships.
Recapitulate means “to repeat the principal stages or phases.” For most, this is perhaps the most recognizable word of the trio. Actually, it is the namesake of recapitulation theory.
Genelle Diaz-Silveira is a master’s student in biology at New York University who is completing her thesis at The New York Botanical Garden.
Harpagophytum procumbens (a.k.a. Devil’s Claw)
In a world saturated with technology, it’s hard to remember the importance of plants to our daily lives. We depend on them for oxygen, food, medicine, clean air, and aesthetic pleasures, yet we devote less mental energy to them than we do to our smartphones and social media accounts.
Luckily, scientists at The New York Botanical Garden do spend some time thinking about plants. By documenting how plants function, how they are related to one another, and what they require from their environment, we aim to learn more about how life evolved on Earth and how we can continue to sustain it.
As a student researcher at the Botanical Garden, I’m doing my part by constructing a phylogeny—an evolutionary family tree—of the plant family Pedaliaceae. Commonly known as the sesame family, Pedaliaceae is rich in species that are both economically and medicinally useful. Examples include Sesamum orientale, which is cultivated for sesame oil, and Harpagophytum procumbens, which is used to treat joint pain caused by arthritis.
Harpagophytum procumbens gets its colloquial name from the plant’s hooked fruit.
It’s the latter species—colloquially called “Devil’s Claw” due to its hooked fruit—that has inspired scientists here to resolve the muddied Pedaliaceae family tree. If we can paint a clear picture of how the family relates to its members as well as to those families closest to it, we may be able to forge a path to future drug discovery.
To elucidate the evolutionary history of Pedaliaceae, I’m primarily using molecular techniques. I’ve extracted DNA from multiple species—at least one representative of each genus—and begun to sequence different genes for each plant sample. The sequences will reveal genetic similarities and differences among my specimens. By analyzing the DNA data, I can come up with a good idea of how Pedaliaceae fits into the mosaic of plant life.
On its face, this may seem like a fairly straightforward endeavor. I obtain samples, extract DNA, sequence the DNA, and make a tree with the data. In actuality, the project has been full of mystery. That is to say, there are only a few contemporary scientists who have devoted time to Pedaliaceae, and herbarium specimens can be hard to come by in the US. These extra difficulties have made the journey extremely exciting.
Evolution can be messy; genetic distinctions among plant species are not always made clear by their physical characteristics. Unresolved families like Pedaliaceae often tentatively include orphan species that don’t clearly fit into one group or another. As this will be one of the first molecular studies of Pedaliaceae, I hope my results will provide enough evidence to definitively place those species. For the time being, I’m just happy to add to the naturalists’ tradition of cataloguing life.
