Coussarea Aubl. includes approximately 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 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 resin, in the vegetative stem apices and sometimes also on the inflorescences (e.g., Coussarea resinosa).
Coussarea is similar to Faramea, which is closely related. 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 uncommon in Coussarea; and reproductive stems with distichous leaf arrangement, vs. usually (or always?) decussate in Coussarea.
Coussarea has also been confused with Palicourea, in particular several Central American species of Palicourea with white nocturnal flowers, rather large salverform corollas, and thin-walled pyrenes were inaccurately included at one point by Standley, L.O. Williams, Dwyer, and Taylor in Coussarea; these species have now been transferred to Palicourea (Taylor et al., 2010).
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 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. The information here is not a comprehensive coverage of Coussarea, but summarizes the information in recent floristic treatments. In particular the plants of the Guianas, Brazil, Paraguay, and Argentina are not covered in detail here.
Author: C.M. Taylor.
The content of this web page was last revised on 5 October 2012.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml