DELPRETE, PIERO G.1* and TIMOTHY J. MOTLEY2. 1Institute of Systematic Botany, The New York Botanical Garden, Bronx, NY 10458; 2The Lewis B. & Dorothy Cullman Program for Molecular Systematics Studies, The New York Botanical Garden, Bronx, NY 10458. - Molecular Systematics of the Chiococceae-Catesbaeeae Complex (Rubiaceae): Flower and Fruit Evolution and Systematic Implications.
Fruit features have historically been used as one of the cardinal
characters for subfamilial, tribal and generic classification in the
family Rubiaceae. Recent phylogenetic studies using rbcL, trnL-F,
rps16 and ITS1&2 and detailed palynological analyses have shown that
the Catesbaeeae-Chiococceae Complex (CCC) is a group that includes
approximately 27 genera and 196 species primarily concentrated in the
Greater Antilles (nearly 70% of the taxa), Central and South America,
and with 3 genera occurring in Malesia and the South Pacific. These
molecular analyses showed that utility of fruit characters must be
carefully reconsidered, and demonstrated that fleshiness of the
mesocarp, placentation, ovule number and insertion are variable within
monophyletic groups. Based on these phylogenies, it was possible to
detect pattern of flower and fruit evolution within this group. All
the analyses clearly indicate that the ancestral fruit type of the CCC
is a multi-seeded capsule, from which were apparently derived leathery
berries and drupaceous fruits in several, separate, evolutionary
events. In addition, the molecular phylogenies prompted a revaluation
of the generic delimitations within the CCC, which will be used for
the ongoing monographic treatment of this group.
Key words: Caribbean, Catesbaeeae, Chiococceae, Morphology, Rubiaceae, Systematics