The monotypic genus Saccifolium has been collected twice on one peak of Cerro de la Neblina (on the Brazil-Venezuela border). The taxon was described into its own family because of its distinct characteristics (Maguire and Pires, 1978). Saccifolium has unique, saccate leaves, a shrubby habit, and Gentianales-like flowers that have a peculiar nectary-like disk at the inside base of the calyx. It has been hypothesized to be closely related to Gentianaceae but no phylogenetic studies have been made until now. We have sequenced and assembled sequences of the trnL intron from Saccifolium as well as over 120 other Gentianaceae. These data were analyzed together with sequences from outgroup taxa representing other families in Gentianales and Asteridae. In the resulting most-parsimonous and parsimony jackknife trees, Saccifolium appears to be sister to Gentiana (which is present in the Andes) and has a basal position in the tribe Gentianeae, a derived clade comprising globally distributed alpine and temperate gentians. Saccifolium is the only member of this clade present on the Guayana (or Brazilian) Shield and is not closely related to any other genera of the family present in this area. The resemblance of Saccifolium flowers to those of some North American Gentiana species and Obolaria suggests that Saccifolium may be a derived member of a northern clade and therefore a relic from an ancient, possibly boreotropical distribution of Gentianeae. This work was supported by the Lewis B. and Dorothy Cullman Foundation. Saccifolium material (Farney et al. 897) was provided by MO.

Key words: biogeography, Gentianaceae, molecular systematics, Neblina, Saccifoliaceae, Saccifolium