Coussarea Aubl. includes a little over 100 species of tropical shrubs and small trees found in moist to wet vegetation in Central and South America. These species are characterized by generally opposite leaves; triangular to rounded stipules; cymose, terminal or rarely axillary inflorescences of varied arrangement, from capitate and sessile to branched to several orders, and with bracts reduced or rarely well developed; white, salverform, generally rather large and showy corollas with four lobes that are valvate in bud; a generally unilocular ovary with one basal ovule; and fleshy, white or yellow fruits with a single, relatively large seed or pyrene, with a papery to firm wall. The flowers apparently are nocturnal and distylous, however at least one species (Coussarea talamancana Standl.) has been demonstrated to be dioecious. The flowers are noted in collection data to be sweetly fragrant, and apparently last one day with the old corollas turning yellow. The anthers are included within the corolla tube in both the long-styled (or pistillate) and short-styled (or staminate) flowers. The fruits are generally spongy, and often lenticellate. Several species are characterized by well developed acarodomatia on the leaves. The axillary buds are often well developed, and their form and size characterize several species. The stipules of Coussarea are variously interpetiolar, shortly united around the stem into a continuous sheath, or completely united into a conical, calyptrate cap. The stipules are generally persistent, but the calyptrate stipules are caducous. Several species produce notable amounts of exudate, which appears to be resinous, in the vegetative stem apices and sometimes also on the inflorescences (e.g., Coussarea resinosa).

The colleters of two Brazilian species of Coussarea were studied by Lopes-Mattos et al. (2015), who found only mucilaginous compounds in them. In another study, Tresmondi et al. (2015) found both mucilage and resin produced by stipule colleters in Guettarda viburnoides. Coussarea paniculata and Coussarea contracta are perhaps the most commonly collected species. Coussarea has not been studied comprehensively, but a number of floristic treatments are available. It has centers of species diversity in southern Central America, the Guianas, the northern and central Andes, and eastern Brazil. Faramea panurensis is also a species of Coussarea (Taylor & Jardim, 2020). The architecture of Coussarea appears varied and to be an adaptation for habitat niche; this has been studied only for a few species so far (e.g., Costa & Santos, 2020). 

Coussarea is similar to Faramea, which is closely related, and these have been confused by various authors (Taylor & Jardim, 2020). In general these differ in their stipules, which are characteristically aristate and also often costate in Faramea vs. smooth and acute to rounded in Coussarea, and their fruits, which are generally leathery and blue or black in Faramea. Addtionally many species of Faramea have blue flowers, which are not known in Coussarea; flattened, frequently costate stems, which are present but uncommon in Coussarea; and reproductive stems with distichous leaf arrangement, vs. commonly (if not generally) decussate in Coussarea. The confusion between Coussarea and Faramea is an old one, and the identity in general of Coussarea has been somewhat unclear and confused, and species of various genera have been included incorrectly in Coussarea by several authors. In particular Coussarea was sometimes confused with Rudgea, at least in part because the identity of Rudgea was also unclear.

A particular confusion arose when Standley and some subsequent authors characterized Coussarea basically by its triangular to rounded stipules, paniculiform terminal inflorescences, generally well developed corollas that are white and seem to be nocturnal, valvate corolla lobes, and fleshy fruits with one or two large seeds with thin seed coats or pyrene walls. Several species from Mexico and Central America that were long classified in Coussarea have these features and five-merous flowers with the anthers partially to fully exserted in their short-styled form, and purple to purple-black fruits with two planoconvex seeds or pyrenes. These species were transferred to Palicourea by Taylor et al. (2010), and these flower and fruit characters are characteristic for Palicourea but with the removal of these species, no longer known in Coussarea.

Coussarea has also sometimes been confused with Ladenbergia, which has similar nocturnal white corollas with the lobes valvate in bud; however Ladenbergia has stipules that are held erect and flat together in bud ("back-to-back"), bilocular ovaries with numerous ovules, and capsular fruits. Coussarea has also been confuse with Raritebe (Kirkbride, 1979), which has nocturnal white flowers similar to those of several Coussarea species and similar interpetiolar obtuse stipules, but differs in its baccate fruits with numerous small seeds.

Author: C.M. Taylor.
The content of this web page was last revised on 30 April 2020.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml

• Taylor, C. M., D. H. Lorence & R. E. Gereau. 2010. Rubiacearum americanarum magna hama pars XXV: The nocturnally flowering Psychotria domingensis-Coussarea hondensis group plus three other Mesoamerican Psychotria species transfer to Palicourea. Novon 20(4): 481–492.
• Taylor, C. M. 1999. Rubiaceae-Coussareeae. 62: 245–314. In G. W. Harling & L. Andersson (eds.) Fl. Ecuador. University of Göteborg, Göteborg.
• 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. 2001. Rubiacearum americanarum magna hama pars III. Five new species and a new subspecies of Coussarea (Coussareae) from Central America and Colombia. Novon 11(1): 135–142.
• Kirkbride, Jr., J. H. 1979. Raritebe, an overlooked genus of the Rubiaceae. Brittonia 31(2): 299–312.
• Taylor, C. M. & J. G. Jardim. 2020. Rubiacearum americanarum magna hama pars XLVI: New species and taxonomic changes in Faramea of Central and South America (Rubiaceae, Coussareeae). Novon 28(2): 108–142.
• Lopes-Mattos, K.L.B., S.A.P. Otuki, A.A. Azevedo, Z.V. pereira & R. M. S. A. Meira. 2015. Colleters in 10 secies belonging to three tribes of Rubiaceae: morphoanatomical diversity and potential as useful charactrs for taxonomy. NRC Research Press Botany, 93: 425–434.
• Costa, R. C. da & F. A. M. dos Santos. 2020. Differences in architecture and performance between two subsubcanopy. Biotropica 52: 415–420.
• Tresmondi, F. , A. Nogueira, E. Guimarães & S. R. Machado. 2015. Morphology, secretion composition, and ecological aspects of stipular colleters in Rubiaceae species from tropical forest and savanna. Sci. Nature 102(73): 1–15.