Two new South American species of Croton (Euphorbiaceae) and their phylogenetic affinities

Two rarely collected species of Croton from South America are des cribed and illustrated. Croton chimboracensis P.E. Berry & Riina is localized in western Andean Ecuador and is sister to Croton sect. Adenophyllum Griseb. Croton abonari Riina & P.E. Berry is known from a single location in Amazonian Brazil; it resembles both C. sampatik Müll. Arg. and members of Croton sect. Cuneati (G.L. Webster) Riina & P.E. Berry, but C. abonari can be easily distinguished from both groups by distinctive morphological characters Se describen e ilustran dos especies raras de Croton de Suramérica. Croton chimboracensis P.E. Berry & Riina está localizada en los Andes occidentales de Ecuador y es hermana del clado de Croton sect. Adenophyllum Griseb. Croton abonari Riina & P.E. Berry se conoce de una sola localidad en la Amazonia de Brasil; es similar tanto a C. sampatik Müll. Arg. y a miembros de la sección Cuneati (G.L. Webster) Riina & P.E. Berry, pero C. abonari se puede diferenciar de ambos grupos por varios caracteres morfológicos distintivos.