Research Training Program

Smithsonian Institution
National Museum of Natural History

PROJECT SUMMARY
1997

Mac H. Alford
Mississippi College
Clinton, Mississippi
 Mac Alford
Robert B. Faden, Ph.D.
Supervising Scientist
Department of Botany
"The combination of lectures, tours, discussions and research has heightened my awareness of natural history issues and has allowed me to learn valuable classical techniques in the field of botany. Furthermore, my peers in systematics whom I have met through the program have become dear friends and have challenged my thinking."

A New Species of Commelina (Commelinaceae) from Tanzania

ABSTRACT
Commelinaceae is a plant family which includes spiderways, dayflowers, and wandering Jews. Tropical Africa is the center of diversity within this family. One genus in this family, the dayflowers or Commelina, consists of about sixty species in tropical east Africa and many new species from this area have been described recently. Because of the large number of species represented, becoming acquainted with the species of Commelina in tropical east Africa is central to understanding the ecology, speciation, phylogeny, and character significance of the genus as a whole. Collections in Tanzania during the summer of 1996 turned up a new species of Commelina, provisionally called Commelina polhillii, which is very similar to Commelina subulata. Plants were grown for study in the Smithsonian greenhouse from seeds collected in the field. From these plants and herbarium collections, the characters of the potentially two different species were investigated. The primary difference between the two species is seed shape and size. Because other macroscopic characters did not prove to be beneficial, differentiation of species was also investigated using cytological and anatomical techniques. The cytological technique of counting chromosomes and the anatomical technique of sectioning leaves have revealed additional information necessary for a complete understanding of the two species. Further studies with Commelina subulata cytology and anatomy will help to resolve the taxonomic questions.

This research was supported by a grant from the Office of the Director of the National Museum of Natural History.