Pagameopsis includes two species of shrubs found in wet scrub vegetation in the tepuis of the Guayana Highlands, in northeastern South America. These plants are characterized by their rather stout, little-branched stems; tissues without raphides; narrow to elliptic, leathery leaves that are paired and often clustered at the ends of the stems due to the stems not much elongating; truncate persistent stipules that interpetiolar and also fused to the bases of the leaves, and shortly setose; terminal pedunculate inflorescences with one or usually several small bracteate heads in a cymose arrangement; small 5-6-merous flowers that are fused together in groups by their ovaries; a pubescent disk; tubular blue to purple corollas with valvate lobes and a fenestrate tube; and small fruits that are indehiscent and drupaceous, forming a single 2-celled pyrene with one seed in each cell. The inflorescences are sometimes displaced to a pseudoaxillary position as the stems continue to grow. The flowers are small, with the corollas about 3.5-5.5 mm long, and the calyx lobes are about as long as the corolla tube or sometimes as the entire corolla. The flowers are unusual in their pubescent disk and corollas with preformed slits in the tube. The flowers are also unusual in their partial to complete fusion at the ovaries. Whether the fruits are fleshy or dry is not entirely clear; they have been described as fleshy (Taylor et al., 2004) but may actually be dry at maturity. Pagameopsis maguirei is the more commonly collected species.

Pagemeopsis was studied by Piesschaert et al. (2001) in detail, including its wood anatomy. Pagameopsis was included by Steyermark and others in the Tribe Psychotrieae, in part because these plants were considered related to Pagamea, but this classification is problematic.The genera of Psychotrieae of Steyermark's time have since been separated into two tribes and several were found to be morphologically incongruent with either of those tribes, including Pagameopsis (Taylor, 1996; Piesschaert et al., 2001).This genus has not been studied with molecular data, and its unusual or reduced characteristics do not clarify its relationships within the family. Piesschaert et al. (2001) noted several of its features that are discordant in the subfamily Rubioideae, but were not able to suggest a better classification.

The habit of these plants is generally similar to that of various other species of páramo and open, high-elevation scrub habitats, but unusual in Rubiaceae. Nothing is known of the pollination or dispersal of these plants. Steyernark (1965) recognized several infraspecific taxa of Pagameopsis maguirei, but these were not separated by Taylor et al. as discussed there (2004: 679). The two Pagameopsis species appear quite distinct as illustrated there (Taylor et al, 2004: 678, fig. 540-541), but the plants vary in size, pubescence, and other features markedly even in a local area, and the species are reliably separated only by the pubescence details and inflorescence size noted in the key there (2004: 679). Subsequent study finds, in fact, that Pagameopsis maguirei subsp. pusillus actually is a synonym of Pagameopsis garryoides. 

Pagameopsis is similar in many features to Coryphothamnus and Aphanocarpus, which are also found on tepuis in the same region. These other two genera can be separated by their verticillate leaves, subcapitate inflorescences, and flowers and fruits that are not fused to each other. Pagamea can be separated from Pagameopsis by its stipules fused into a well developed tube that is setose at the top, and its superior ovary and fruit. Pagameopsis is also similar in several features to Coccochondra, with axillary inflorescences and the flowers not fused. 

Author: C.M. Taylor.
The content of this web page was last revised on 15 September 2020.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml

• Taylor, C. M., J. A. Steyermark, P. G. Delprete, A. Vincentini, R. Cortés-Ballén, D. C. Zappi, C. H. Persson, C. B. Costa & E. Anunciação. 2004. Rubiaceae. 8: 497–847. In J. A. Steyermark, P. E. Berry & B. K. Holst (eds.) Fl. Venez. Guayana. Missouri Botanical Garden Press, St. Louis.
• Taylor, C. M. 1996. Overview of the Psychotrieae (Rubiaceae) in the Neotropics. Opera Bot. Belg. 7: 261–270.
• Piesschaert, F., S. Jansen, I. Jaimes, E. Robbrecht & E. Smets. 2001 [2002]. Morphology, anatomy, and taxonomic position of Pagameopsis (Rubiaceae–Rubioideae). Brittonia 53(4): 490–504.