John Z

John Zaborsky

T.A. for Plant Systematics (Botany 400) 

Lab 303

Office Hours: TBD 

258 Birge Hall, 262-4422


I have a deep interest (perhaps obsession) with succulent plants. As a result, my research centers on two genera of succulent trees, both of which are members of the sesame family (Pedaliaceae). Endemic to Madagascar, Uncarina contains 14 species that grow throughout the arid regions of the island. Some species have large ranges while others are confined to small areas and are rare. All species have unique, burr-like fruits that easily get stuck in the fur of mammals, aiding in dispersal. There appears to be some soil-specificity among the species, which grow on various substrates including sand dunes, limestone outcrops, and clay soils.

Sesamothamnus contains six species with an unusual distribution: three are endemic to Namibia, one is confined to southern Africa, and two grow in Tanzania, Kenya, and Somalia. No one has yet been able to explain why the species are found in such distant areas or why there are no populations connecting them.

These plants provide numerous interesting questions that I will be exploring: What caused woodiness to evolve two separate times in a family that contains primarily herbaceous plants? How did Uncarina become the sole member of Pedaliaceae native to Madagascar? What has caused the geographical separation of the six species in Sesamothamnus? Uncarina fruits may have been dispersed by recently extinct megafauna: what does this mean for their continued survival? How do moisture, soil, and temperature conditions shape the characteristics of succulent trees (e.g. leaf shape and size, growth form).

I am also interested in the flora of my home state: Wisconsin. I have been exploring the wild lands of the Badger State for over 20 years and in the process have gained a deep knowledge of its plants and natural communities.

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