CHROMOSOME SURVEY OF THE RUBIACEAE

The present knowledge of karyological characters, including basic numb ers, ploidy levels, chromosome structures, karyotypes, interphase nucl ear types, and DNA contents, and the broad range of variation for most of these characters within Rubiaceae (excluding Rubieae) are summariz ed. These data are related to the presently existing systematic concep ts of the family. The use of karyological characters is exemplified in some taxonomically critical groups: Subfamily Antirheoideae sensu Rob brecht appears heterogeneous with regard to basic numbers and chromoso me structure; it contains chromosomally homogeneous tribes (e.g., Vang uerieae or Guettardeae), but also groups with internal variation (such as the tribe Knoxieae or the genus Chiococca). Available chromosome d ata of the tribe Cinchoneae sensu Robbrecht seem to be in accordance w ith its morphologically and molecular-based subdivision in three tribe s: viz. Cinchoneae s. str., Calycophylleae, and Coptosapelteae. The tr ibe Chiococceae sensu Bremer consists of at least two distinct entitie s characterized by their chromosome morphology and basic numbers: the former tribe Condamineeae, and the genera Chiococca and Exostema. A po ssible subdivision of Rondeletia is indicated by three different basic numbers (x = 9, x = 10, x = 11) occurring in the genus, while chromos ome data give no hints regarding the position of Wendlandia and Sipane a in the tribe Rondeletieae. The tribe Isertieae comprises genera with basic numbers of x = 9, x = 10, and x = 11. Thus the tribal position of Acranthera (x = 10), Heinsia (x = 11), and Mycetia (x = 11) cannot be decided on the basis of chromosome numbers alone. Sabicea has taxa with either x = 9 or x = 11; morphological studies are required to che ck the generic delimitations. The close relationship of Panridiantha a nd Urophyllum is supported by karyomorphology and basic number. A poss ible origin of the Spermacoce out of the tribe Hedyotideae is discusse d.